Said By Aron Schatz
You could also use a client such as Gaim: http://gaim.sourceforge.net/
Connects to major networks without the bloat.
Said By Psychotix
BitWise IM: The power and privacy you should expect from IM
Text, File Sharing, Whiteboards, Voice, Encryption and more
Best IM out the Fileshareing is nice Encryption very nice and the Whiteboard, Voice if you like IM'ing you gotta check this out
Oh yeah Did I mention Cross Platform Linux, Windows, And Mac ;-)
http://www.bitwiseim.com/signup.php