In case you hadn't heard, Google now has a chat client. You can get it from
http://www.google.com/talk/. It's Windoze only, unfortunately, but their server uses the open Jabber protocol. That means you can use just about any multi-protocol chat client to connect (i use
gaim). For some reason, though, they haven't connected their server to other Jabber servers out there, so you can only talk to other Google Talk users (similar to the other big IM players). Maybe once it's out of beta testing they'll rethink that...
The Windoze client apparently allows you to use voice chat, and automatically adds your gmail contacts to your friends list. I can't vouch for that, though...
To use the service, you have to have a gmail account. If you don't have one yet, you can get one if you have a U.S. cell 'phone number. Or bug someone for an invitation... in a reply to this, for instance :) See you in chat...