diff --git a/ChangeLog b/ChangeLog
index 0c89ae7e9cb..f028a742597 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1167,4 +1167,10 @@
 	* arch/arm/src/lpc17xx/lpc17_serial.c - Improved logic to handle
 	  missed TX interrupts.
 	* arch/arm/src/lpc17xx/lpc17_ssp.c - Fix a hard fault during SSP
-	  initialization.
\ No newline at end of file
+	  initialization.
+	* configs/nucleus2g/src/up_led.c - Change how LEDs are controlled
+	  so that they can be used both for NuttX instrumentation and
+	  by application software.
+	* include/net/uip/igmp.h and uip-igmp.h - Add header files ini
+	  preparation for NuttX IGMP support
+	* net/uip/uip_igmpinit.c, uip_igmpgroup.c - Add IGMP logic.
diff --git a/Documentation/NuttX.html b/Documentation/NuttX.html
index 9d5530b0244..6ca1dbb5452 100644
--- a/Documentation/NuttX.html
+++ b/Documentation/NuttX.html
@@ -8,7 +8,7 @@
   <tr align="center" bgcolor="#e4e4e4">
     <td>
       <h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1>
-      <p>Last Updated: July 3, 2010</p>
+      <p>Last Updated: July 7, 2010</p>
     </td>
   </tr>
 </table>
@@ -1843,6 +1843,12 @@ nuttx-5.8 2010-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 	  missed TX interrupts.
 	* arch/arm/src/lpc17xx/lpc17_ssp.c - Fix a hard fault during SSP
 	  initialization.
+	* configs/nucleus2g/src/up_led.c - Change how LEDs are controlled
+	  so that they can be used both for NuttX instrumentation and
+	  by application software.
+	* include/net/uip/igmp.h and uip-igmp.h - Add header files ini
+	  preparation for NuttX IGMP support
+	* net/uip/uip_igmpinit.c, uip_igmpgroup.c - Add IGMP logic.
 
 pascal-2.1 2010-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 
diff --git a/include/net/uip/uip-arch.h b/include/net/uip/uip-arch.h
index 3184ac0f7cd..939c60450d3 100644
--- a/include/net/uip/uip-arch.h
+++ b/include/net/uip/uip-arch.h
@@ -176,7 +176,7 @@ struct uip_driver_s
   /* IGMP group list */
 
 #ifdef CONFIG_NET_IGMP
-  FAR struct igmp_group_s *grplist;
+  sq_queue_t grplist;
 #endif
 
   /* Driver callbacks */
diff --git a/include/net/uip/uip-igmp.h b/include/net/uip/uip-igmp.h
index 56c6a17b300..4b7db8fc191 100755
--- a/include/net/uip/uip-igmp.h
+++ b/include/net/uip/uip-igmp.h
@@ -90,6 +90,20 @@
 #define IGMP_DELAYING_MEMBER     1
 #define IGMP_IDLE_MEMBER         2
 
+/* Group flags */
+
+#define IGMP_PREALLOCATED        1
+#define IGMP_LASTREPORT          2
+
+#define SET_PREALLOCATED(f)      do { (f) |= IGMP_PREALLOCATED; } while (0)
+#define SET_LASTREPORT(f)        do { (f) |= IGMP_LASTREPORT; } while (0)
+
+#define CLR_PREALLOCATED(f)      do { (f) &= ~IGMP_PREALLOCATED; } while (0)
+#define CLR_LASTREPORT(f)        do { (f) &= ~IGMP_LASTREPORT; } while (0)
+
+#define IS_PREALLOCATED(f)       (((f) & IGMP_PREALLOCATED) != 0)
+#define IS_LASTREPORT(f)         (((f) & IGMP_LASTREPORT) != 0)
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -174,7 +188,7 @@ struct igmp_group_s
   struct igmp_group_s *next;    /* Implements a singly-linked list */
   uip_ipaddr_t         grpaddr; /* Group IP address */
   WDOG_ID              wdog;    /* WDOG used to detect timeouts */
-  bool                 lastrpt; /* Indicates the last to report */
+  uint8_t              flags;   /* See IGMP_ flags definitions */
   uint8_t              state;   /* State of the group */
   uint8_t              msgid;   /* Pending message ID (if non-zero) */
 };
diff --git a/net/uip/Make.defs b/net/uip/Make.defs
index 31011ffa35c..4f94b4eab85 100644
--- a/net/uip/Make.defs
+++ b/net/uip/Make.defs
@@ -79,7 +79,7 @@ endif
 endif
 
 ifeq ($(CONFIG_NET_IGMP),y)
-UIP_CSRCS += uip_igmpinit.c
+UIP_CSRCS += uip_igmpinit.c uip_igmpgroup.c
 endif
 
 endif
diff --git a/net/uip/uip_igmpgroup.c b/net/uip/uip_igmpgroup.c
new file mode 100755
index 00000000000..295800941e0
--- /dev/null
+++ b/net/uip/uip_igmpgroup.c
@@ -0,0 +1,291 @@
+/****************************************************************************
+ * net/uip/uip_igmpgroup.c
+ * IGMP group data structure management logic
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * The NuttX implementation of IGMP was inspired by the IGMP add-on for the
+ * lwIP TCP/IP stack by Steve Reynolds:
+ *
+ *   Copyright (c) 2002 CITEL Technologies Ltd.
+ *   All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ *
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 2. Redistributions in binary form must reproduce the above copyright 
+ *    notice, this list of conditions and the following disclaimer in the 
+ *    documentation and/or other materials provided with the distribution. 
+ * 3. Neither the name of CITEL Technologies Ltd nor the names of its contributors 
+ *    may be used to endorse or promote products derived from this software 
+ *    without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY CITEL TECHNOLOGIES AND CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED.  IN NO EVENT SHALL CITEL TECHNOLOGIES OR CONTRIBUTORS BE LIABLE 
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
+ * SUCH DAMAGE. 
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <queue.h>
+#include <debug.h>
+
+#include <arch/irq.h>
+#include <nuttx/arch.h>
+
+#include <net/uip/uip.h>
+#include <net/uip/uip-igmp.h>
+
+#include "uip_internal.h"
+
+#ifdef CONFIG_NET_IGMP
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#ifdef CONFIG_NET_IPv6
+#  error "IGMP for IPv6 not supported"
+#endif
+
+#ifndef CONFIG_PREALLOC_IGMPGROUPS
+#  define CONFIG_PREALLOC_IGMPGROUPS 4
+#endif
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/* malloc() cannot be called from an interrupt handler.  To work around this,
+ * a small number of IGMP groups are preallocated just for use in interrupt
+ * handling logic.
+ */
+
+static struct igmp_group_s g_preallocgrps[CONFIG_PREALLOC_IGMPGROUPS];
+static FAR sq_queue_t g_freelist;
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name:  uip_grpalloc
+ *
+ * Description:
+ *   Allocate a new group from heap memory.
+ *
+ * Assumptions:
+ *   Calls malloc and so cannot be called from an interrupt handler.
+ *
+ ****************************************************************************/
+
+static inline FAR struct igmp_group_s *uip_grpheapalloc(void)
+{
+  return (FAR struct igmp_group_s *)zalloc(sizeof(struct igmp_group_s));
+}
+
+/****************************************************************************
+ * Name:  uip_grpprealloc
+ *
+ * Description:
+ *   Allocate a new group from the pre-allocated groups.
+ *
+ * Assumptions:
+ *   This function should only be called from an interrupt handler (or with
+ *   interrupts disabled).
+ *
+ ****************************************************************************/
+
+static inline FAR struct igmp_group_s *uip_grpprealloc(void)
+{
+  FAR struct igmp_group_s *group = (FAR struct igmp_group_s *)sq_remfirst(&g_freelist);
+  if (group)
+    {
+      memset(group, 0, sizeof(struct igmp_group_s));
+      group->flags = IGMP_PREALLOCATED;
+    }
+  return group;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name:  uip_grpinit
+ *
+ * Description:
+ *   One-time initialization of group data.
+ *
+ * Assumptions:
+ *   Called only during early boot phases (pre-multitasking).
+ *
+ ****************************************************************************/
+
+void uip_grpinit(void)
+{
+  FAR struct igmp_group_s *group;
+  int i;
+
+  for (i = 0; i < CONFIG_PREALLOC_IGMPGROUPS; i++)
+    {
+      group = &g_preallocgrps[i];
+      sq_addfirst((FAR sq_entry_t *)group, &g_freelist);
+    }
+}
+
+/****************************************************************************
+ * Name:  uip_grpalloc
+ *
+ * Description:
+ *   Allocate a new group from heap memory.
+ *
+ * Assumptions:
+ *   May be called from either user or interrupt level processing.
+ *
+ ****************************************************************************/
+
+FAR struct igmp_group_s *uip_grpalloc(FAR struct uip_driver_s *dev, FAR uip_ipaddr_t *addr)
+{
+  FAR struct igmp_group_s *group;
+  irqstate_t flags;
+
+  nllvdbg("addr: %08x dev: %p\n", *addr, dev);
+  if (up_interrupt_context())
+    {
+      group = uip_grpheapalloc();
+    }
+  else
+    {
+      group = uip_grpprealloc();
+    }
+
+  /* Check if we succesfully allocated a group structure */
+
+  if (group)
+    {
+      /* Initialize the non-zero elements of the group structure */
+
+      uip_ipaddr_copy(group->grpaddr, addr);
+
+      /* Interrupts must be disabled in order to modify the group list */
+
+      flags = irqsave();
+
+      /* Add the group structure to the list in the device structure */
+
+      sq_addfirst((FAR sq_entry_t*)group, &dev->grplist);
+      irqrestore(flags);
+    }
+  return group;
+}
+
+/****************************************************************************
+ * Name:  uip_grpfind
+ *
+ * Description:
+ *   Find an existing group.
+ *
+ * Assumptions:
+ *   May be called from either user or interrupt level processing.
+ *
+ ****************************************************************************/
+
+FAR struct igmp_group_s *uip_grpfind(FAR struct uip_driver_s *dev, FAR uip_ipaddr_t *addr)
+{
+  FAR struct igmp_group_s *group;
+  irqstate_t flags;
+
+  /* We must disable interrupts because we don't which context we were called
+   * from.
+   */
+
+  flags = irqsave();
+  for (group = (FAR struct igmp_group_s *)dev->grplist.head; group; group = group->next)
+    {
+      if (uip_ipaddr_cmp(&group->grpaddr, addr))
+        {
+          break;
+        }
+    }
+  irqrestore(flags);
+  return group;
+}
+
+/****************************************************************************
+ * Name:  uip_grpallocfind
+ *
+ * Description:
+ *   Find an existing group.  If not found, create a new group for the
+ *   address.
+ *
+ * Assumptions:
+ *   May be called from either user or interrupt level processing.
+ *
+ ****************************************************************************/
+
+FAR struct igmp_group_s *uip_grpallocfind(FAR struct uip_driver_s *dev, FAR uip_ipaddr_t *addr)
+{
+  FAR struct igmp_group_s *group = uip_grpfind(dev, addr);
+  if (!group)
+    {
+      group = uip_grpalloc(dev, addr);
+    }
+  return group;
+}
+
+/****************************************************************************
+ * Name:  uip_grpfree
+ *
+ * Description:
+ *   Release a previously allocated group.
+ *
+ * Assumptions:
+ *   May be called from either user or interrupt level processing.
+ *
+ ****************************************************************************/
+
+void uip_grpfree(FAR struct uip_driver_s *dev, FAR struct igmp_group_s *group)
+{
+  /* First, remove the group structure from the group list in the device
+   * structure
+   */
+
+  irqstate_t flags = irqsave();
+  DEBUGASSERT(sq_rem((FAR sq_entry_t*)group, &dev->grplist) != NULL);
+  if (IS_PREALLOCATED(group->flags))
+    {
+      sq_addlast((FAR sq_entry_t*)group, &g_freelist);
+      irqrestore(flags);
+    }
+  else
+    {
+      irqrestore(flags);
+      free(group);
+    }
+}
+
+#endif /* CONFIG_NET_IGMP */
diff --git a/net/uip/uip_igmpinit.c b/net/uip/uip_igmpinit.c
index 32d986835df..9dceb0134a7 100755
--- a/net/uip/uip_igmpinit.c
+++ b/net/uip/uip_igmpinit.c
@@ -68,6 +68,10 @@
 uip_ipaddr_t g_allsystems;
 uip_ipaddr_t g_allrouters;
 
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
 /****************************************************************************
  * Name:  uip_igmpinit
  *
diff --git a/net/uip/uip_internal.h b/net/uip/uip_internal.h
index af20911d320..8570fba5b49 100644
--- a/net/uip/uip_internal.h
+++ b/net/uip/uip_internal.h
@@ -223,6 +223,12 @@ EXTERN void uip_igmpinput(struct uip_driver_s *dev);
 EXTERN void uip_grpinit(void);
 EXTERN FAR struct igmp_group_s *uip_grpalloc(FAR struct uip_driver_s *dev,
                                              FAR uip_ipaddr_t *addr);
+EXTERN FAR struct igmp_group_s *uip_grpfind(FAR struct uip_driver_s *dev,
+                                            FAR uip_ipaddr_t *addr);
+EXTERN FAR struct igmp_group_s *uip_grpallocfind(FAR struct uip_driver_s *dev,
+                                                 FAR uip_ipaddr_t *addr);
+EXTERN void uip_grpfree(FAR struct uip_driver_s *dev,
+                        FAR struct igmp_group_s *group);
 
 /* Defined in TBD */