Clifford Bleszinski, the design director at Epic Games has given a short interview to Game Informer on the topic of upcoming Unreal Engine 4 and what it can do.
It is not the most in-depth discussion with it in clocking in at just over 3 minutes. It is however, nice to to hear some of the details from the proverbial horse's mouth.
If you are wanting a little more entertainment/information, you might also try this article as well. It's another short video with Shane Claude, Epic's art director, and Mark Rein, Epic's Vice President, showing off a series of mini games that the pair cooked up in the new engine on their own.