Just to let you know, last August, at Wizard World Chicago, there was a super secret panel that I was fortunate to go to. Waking up at the crack of dawn, and waiting in lines for pretty much the entire day. It didn't start until the evening. They had a Q and A session with Christopher and Jonathan Nolan, David Goyer, Christian Bale, Aaron Eckhart, and Gary Oldman. They could only talk about experiences, and not get in too much depth about the story.

At the end of the Q&A, they showed a couple of minute in length of footage they shot up until that point (which they said they were half through). Most of what I remember we have seen in trailers by now. But one we have not is a scene that was at the very end. There was a shadowed figure cut off frame, with another individual facing him (I can't remember who it was, but it wasn't a main cast member). That person said "Harvey Dent? I thought you were dead." The shadowed figure replied, "Only half."

And also recently, Aaron Eckhart gave an interview, which he said, when you see Two-Face, paraphrasing, "it will literally make you sick in your stomach."

Harvey Dent gets his face burned off. Most likely by The Joker? Harvey then becomes Two-Face and does a crusade against crime by killing off criminals [like the end of The Long Halloween].