Well, since the film is scheduled for late summer 2008 (last I heard, anyway), I think maybe around Summer of '07 they should launch an early trailer, similar to the way that Universal did it for "Hulk". Just keep it dark, moody, secretive...maybe a laugh from the Joker, or a few lines from the end of "Begins" over background footage, followed by a cool tagline. Here's an idea I had floating around in my head...
Trailer starts, with the usual WB and DC Comics logos in monochrome, followed by a very faint rendition of the "Begins" theme. We see the lock being tripped on the doors from Arkham, and are sent back to the famous lines from Lt. James Gordon.
Gordon: "The Narrows is lost...What about escalation?"
Batman: "Escalation?"
Gordon: "Take this guy. Armed robbery, double homicide..."
[We see shadows flickering on buildings and such, followed by muffled gunshots and a sound of psychotic laughter.]
Gordon (continued):"...leaves a calling card." (shows the Joker card)
Batman (voice only): "I'll look into it..."
[Cut to black, as another laugh is heard, followed by a teaser card that reads: "The Clown...the Bat...Summer 2008".]
Just a scenario I was thinking about. What do ya think?