Jabber open-source instant messaging system nears public release

“Jabber is an Instant Messaging System, similiar to ICQ or AIM,
but yet far different. It is open-source, absolutely free, simple,
fast, extensable, modularized, cross platform, and designed with
the future in mind. Jabber has been designed from the gound up to
serve the needs of it’s users, and maintain compatability with
other messaging systems. As a Jabber user, you can still
communicate directly with ICQ users, AIM users, and other
communication systems transparently.”

Learn more about Jabber.