diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index d9e1652893..9275258de7 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -12,7 +12,7 @@
       <h1><big><font color="#3c34ec">
         <i>NuttX RTOS Porting Guide</i>
       </font></big></h1>
-      <p>Last Updated: May 13, 2010</p>
+      <p>Last Updated: July 12, 2010</p>
     </td>
   </tr>
 </table>
@@ -2464,6 +2464,11 @@ extern void up_ledoff(int led);
     structures.  The system manages a pool of preallocated
     watchdog structures to minimize dynamic allocations
   </li>
+  <li>
+    <code>CONFIG_PREALLOC_IGMPGROUPS</code>: Pre-allocated IGMP groups are used
+    Only if needed from interrupt level group created (by the IGMP server).
+    Default: 4
+  </li>
   <li>
     <code>CONFIG_DEV_PIPE_SIZE</code>: Size, in bytes, of the buffer to allocated
     for pipe and FIFO support (default is 1024).
@@ -2645,6 +2650,14 @@ extern void up_ledoff(int led);
     <code>CONFIG_NET_ICMP_PING</code>: Provide interfaces to support application level
     support for sending ECHO (ping) requests and associating ECHO replies.
   </li>
+  <li>
+    <code>CONFIG_NET_IGMP</code>:  Enable IGMPv2 client support.
+  </li>
+  <li>
+    <code>CONFIG_PREALLOC_IGMPGROUPS</code>: Pre-allocated IGMP groups are used
+    Only if needed from interrupt level group created (by the IGMP server).
+    Default: 4
+  </li>
   <li>
     <code>CONFIG_NET_PINGADDRCONF</code>: Use "ping" packet for setting IP address
   </li>
diff --git a/configs/README.txt b/configs/README.txt
index bbfe9946af..7bfdd65dc7 100644
--- a/configs/README.txt
+++ b/configs/README.txt
@@ -313,6 +313,9 @@ defconfig -- This is a configuration file similar to the Linux
 		CONFIG_PREALLOC_MQ_MSGS - The number of pre-allocated message
 		  structures.  The system manages a pool of preallocated
 		  message structures to minimize dynamic allocations
+		CONFIG_PREALLOC_IGMPGROUPS - Pre-allocated IGMP groups are used
+		  only if needed from interrupt level group created (by the IGMP server).
+		  Default: 4.
 		CONFIG_MQ_MAXMSGSIZE - Message structures are allocated with
 		  a fixed payload size given by this settin (does not include
 		  other message structure overhead.
@@ -405,6 +408,10 @@ defconfig -- This is a configuration file similar to the Linux
 		CONFIG_NET_ICMP_PING - Provide interfaces to support application level
 		  support for sending ECHO (ping) requests and associating ECHO
 		  replies.
+		CONFIG_NET_IGMP - Enable IGMPv2 client support.
+		CONFIG_PREALLOC_IGMPGROUPS - Pre-allocated IGMP groups are used
+		  only if needed from interrupt level group created (by the IGMP server).
+		  Default: 4.
 		CONFIG_NET_PINGADDRCONF - Use "ping" packet for setting IP address
 		CONFIG_NET_STATISTICS - uIP statistics on or off
 		CONFIG_NET_RECEIVE_WINDOW - The size of the advertised receiver's