BFG is right, this is the 3rd similar app that I've seen that should have been developed by companies but instead is ported by individuals (Teamspeex, The XFire thingy, Chax)
Adium is very promising, if only apple would take them under their wing like they did with Audion to form iTunes.
Adium is open-source, you can say that the guys behind Audion got bought up
And they managed to get the guy behind Proteus, hes currently working on QA with ichat I believe.
But if, in theory took Adium under their wing, contributed code to it. It would simply outmatch any other IM app out there. But it might be AOL that says no. With their video and their own service.