There are quite a number of thread on vbulletin.com discussing vB 3, including many hints of new features from the developers. Sorry that's there's no neat organized list of features yet, but it's still too premature to list the complete feature set.
http://www.vbulletin.com/forum/showt...ighlight=hints
http://www.vbulletin.com/forum/showt...ighlight=hints
http://www.vbulletin.com/forum/showt...ighlight=hints
http://www.vbulletin.com/forum/showt...ighlight=hints