Adium is a free instant messaging application for Mac OS X that can connect to AIM, MSN, Jabber, Yahoo, and more.
* Fixed sending of invalid XML when asked for our version information in XMPP, which effectively broke XMPP connectivity. (Bug introduced in 1.2.6)
* Improved handling of invalid XML over XMPP
* Hopefully fixed a bug which caused an XMPP contact to infinitely flip between two groups shortly after authorization
Internet and communication
Mac OS X
Product page: here