Chat Core (part of the Colloquy project) is a BSD licensed open source ObjC IRC and SILC framework.
Cool, I think this’ll come in handy� �DustinVoss
Proteus also has its chat services available, although I know nothing about them.
Proteus’s imservices is a daemon for insulation from the GPL. It used to incorporate libfaim (AIM-TOC), libfiretalk (AIM-OSCAR), libgg (Gadu-Gadu), libicq2000, libjabber, libyahoo, libyahoo2, msnlib, and Proton’s Proteus Plugin (which was RendezVous Plugin for Proteus before TIBCO’s lawyers heard of it); version 4 uses libgaim, presumably replacing most of the above. The source is supposed to be available at indigofield.com via SubVersion and ViewCVS, neither of which I’ve ever seen working.
And of course XChat Aqua’s source is available - http://xchataqua.sourceforge.net/
A backup copy of Acid, a jabber library written in Cocoa is available here (since it isn’t hosted on jabberstudio.org anymore) http://code.kluivers.nl/wsvn/Projects/Acid/trunk/#/Acid/trunk/