Wow! I had to re-read this a couple of times just to wrap my head around it. But while I do it once more for good measures, check out what director Christopher Nolan is saying in regards to the upcoming
The Dark Knight.
"Harvey Dent (Aaron Eckhart) is a tragic figure, and his story is the backbone of this film. The Joker, he sort of cuts through the film -- he's got no story arc, he's just a force of nature tearing through. Heath has given an amazing performance in the role, it's really extraordinary."
Huh . . . Anyone who's sees the film's IMAX prologue knows -- *SPOILER ALERT!* -- that when we meet The Joker he's able established himself into the criminal underworld. Put together this sequence establishing him as a master manipulator and the online speculation that he may, in fact, have something to do with transforming Dent into Two-Face and the pieces all seem to be falling nicely into place. Even in the trailer (which I've only watched a googol [Look it up!] amount of time) he states "Its all part of the plan".

Marketing wise its a brilliant move diverting all our attention onto The Joker while not giving us crumbs in regards to Two-Face, in regards to either his appearance or his relationship to the plot.
In related news that makes me as giddy as a Mexican schoolgirl at a Menudo concert its been confirmed that Cillian Murphy will reprise his role as The Scarecrow. I loved this guy in
Batman Begins and am thrilled to see he'll back to freak your shit out!