GOIM (Gamers Own Instant Messenger) is a full featured jabber / XMPP client with special features (extensions) for gamers. (e.g. broadcasting a notification when you join a server, or seeing which games others play and joining them with one click on the game icon beside their name).
It also features an InGame Messenger which supports most DX8 games and supports the jabber XFireGateway which allows communication/presence changes/game status changes with your XFire buddies.