You may have also seen some other news about a picture from the set in India that seems to reveal some plot details, but I'm not going to post that, since it's too much of a potential spoiler. In fact, I'm pretty close to checking out of posting entirely, since until the trailer, there won't be much worth posting that isn't a spoiler.
After The Scarecrow, Ra's Al Ghul, The Joker, and Two-Face, who should be Batman's next enemy in the Batman Begins/The Dark Knight series? Well, as of now we know that Tom Hardy will play Bane and Anne Hathaway will play Catwoman.
Check out the master list for all the villains covered. I've pretty much run out by now. Obviously, there are more Batman villains, but not any of significance that I know of. As of February 2009, no one is confirmed as a villain. Not the Johnny Depp Riddler, not Phillip Seymour Hoffman Penguin, nobody.