Third!
I am a .NET (C#) developer in "real life", but have never touched the MP guts. I know there is some code out there for working with the MSN protocol and DLLs, but that's it. Anyone who knows more than I do about this, I'm willing to lend a hand.
I am also interested in doing AIM connectivity too.
One of the downsides to GAIM is the lack of camera support. I don't know much about AIM, but the MSN Messenger product upon installation should have a DLL or ActiveX control for camera in/out. If so, then it can be "hooked" with .NET...