LoopRumors claims to have details on the upcoming iChat update (version 2.0).
As previously reported - reliable MacRumors sources have indicated that the next iChat revision will have Videoconferencing.
LoopRumors adds that Apple is working on "a new compression technology" and wants to achieve a full 30fps... though at what bandwidth is not specified.
Unconfirmed MacRumors submissions claim that it will have "new compatabilities" -- possibly with Jabber, as well in as increased security, and a "security feature" to stop leaks.