Jake of the Web

http://www.pidgin.im/

http://www.ceruleanstudios.com/

Both Trillian and Pidgin (formerly GAIM) are free multi-protocol IM applications. You can use one application to access AIM, ICQ, Yahoo and MSN messengers. The free version of Pidgin and the Pro version of Trillian also allow you to use it for Google Talk and Novell Instant Messenger, which is why I have recently switched from Trillian to Pidgin.