Jabber.org The main page for Jabber developers and people interested in helping Jabber, not for the end user!
Jabber.com Makes custom Jabber client/server solutions for companies and brand name Jabber based IM's. Makes JabberIM a nice simple good looking Jabber client for Windows.
Jabbercentral.com Jabber news site and info for the end user.
hotjabber.com - An info and help site. Has a good WinJab tutorial.
dmoz jabber page - Lots of links related to Jabber.
MacZoop - C++ framework used by Jabbernaut.
GUSI - the POSIX socket library employed for network communication within Jabbernaut
OpenSSL - used for SSL support in Jabbernaut