Pidgin - Pidgin is an easy to use and free chat client used by millions. Connect to AIM, MSN, Yahoo, and more chat networks all at once.
Empathy - Apps/Empathy - GNOME Wiki!
Gajim - Full featured and easy to use Jabber client
IM+ - Chat everywhere! IM+ is the most widely used mobile IM app! Connect all-in-one to MSN, Yahoo!, Goo...
Trillian - Trillian is a decentralized and federated instant messaging platform that lets your whole company send private and group messages, keep tabs on what co-workers are doing, share files, and much more.
Coccinella - Coccinella is a free and open-source cross-platform instant messaging client with a built-in...