Adium - IM Client for Mac

Open Source Instant messaging Client

Adium is a open source instant messaging client for Mac OS X that supports multiple IM networks, including Windows Live Messenger, Yahoo! Messenger, Google Talk, AIM, ICQ, XMPP and OTR. It supports many protocols through the libraries libezv (for Bonjour), MGTwitterEngine (for Twitter), and libpurple (for all other protocols). It is written using Mac OS X's Cocoa API, and it is released under the GNU General Public License and many other licenses for components that are distributed with Adium.