Apple recently seeded a new build of Leopard (Build 9A321) to developers. It is also rumored that Apple may have seeded a separate build to employees. MacRumors has provided information that this build contains a new answering machine feature in iChat.
It appears that these feature is still not fully functional, but provides an interesting look into the future of the iChat application.
The new iChat answering preference tab allows users to record a Video greeting to serve as an answering message when users are away from their desk. The caller may then leave a message. At this time, there only appears to be partial functionality implemented.
MacRumors has also provided this photo: