A trusted source has provided TUAW with a screen-capture of an iChat 4.0 preference pane which hints at an as-yet-unannounced new feature– voicemail. Such a feature would round out the programs VoIP offerings and create a more complete communication experience for users.
Now if only iChat could integrate with Skype and SIP, I wouldn't need a phone at all!
Update: Can it be exclusive if Mac Rumors covered it in Dec? Ah well, here's hope we both don't get matching nastygrams from Apple legal (hey, we love your work!).