It looks like everyones talking about Google's forth coming XMPP/Jabber server at the moment,
Brian Del Vecchio has a page showing connection details for Gaim.
The guts of it are that your "JID" (Jabber User Id) is the same as your Gmail email address, but the Jabber server is talk.google.com. Not all clients appear to let you use a different server than whats in the JID (Gaim and Gossip both do) so you may need to hunt around.
Currently I've been able to talk to other Gmail users ONLY after they've been added to my roster (good for anti spam) and as yet no form of server-to-server comms - this may be due to Google not providing s2s, but may also be related to using a different server hostname than whats mentioned in the JID (I'm unfamiliar with now this actually works, so that may be a non-issue).
This'll be an interesting thing to watch...
Update: Google themselves now have an
official page showing gaim settings.
tags: xmpp google gmail jabber
links: digg this del.icio.us technorati reddit