Interesting but not at all surprising. AOL apparently owns the rights to AIM (AOL Instant Messenger) and got upset because Gaim was using this terminology and threatened to sue the Gaim developers. As a result, the folks at Gaim have changed the name to Pidgin IM. Here's the article from the now Pidgin's website. The good thing is that they're looking to finally release 2.0.0, which has long been in beta. Ive been using the beta version for awhile and it really has some nice improvements.
http://pidgin.im/