Heath Ledger has been chosen as the new Joker in the Batman Begins sequel, The Dark Knight (what, no "Batman Continues"?).
I had hoped that the rumors that Crispin Glover would play the Joker were true. I always like to see Glover working, he's a genuinely creepy guy, and he's got the perfect sharp chin.
But I think Heath Ledger will work. I still haven't seen Brokeback Mountain, but I just watched Lords of Dogtown, in which he plays the drunk/stoned proprietor of a Venice surf/skate shop, and he's great in it. He strikes me as a talented, chameleonlike actor who can be really intense when he wants to be.