The Dark Knight's official trailer is up at A Taste for the Theatrical. (Be sure to click on the "Download Now" graphic, the Joker's a little vague.)
Go watch it. Geek out majorly. It is seriously the COOLEST trailer I have seen since 300. I've shown it to everyone I know. If I could show it to my dog, I would. (He's a bit too young, I think.)
The Joker hanging out of a police car, blissed out?
Rachel Dawes smacking him up?
"You've got some fight in you...I like that!"
It's the stuff a fanboy or girl's dreams are made of.
I've got to say...I don't think that's lipstick on the Joker's face.