Nestor Carbonell has been tapped to play the Mayor of Gotham City, and there's a rumor about a returning face. Variety reports the casting of Lost's Carbonell,  while MTV reports that David Banner has auditioned for a role in Joker's gang, with a character named Gamble.  Eric Roberrs will indeed be plaing Sal Maroni, per the New York Post.  Meanwhile, Maggie Gyllenhaal will have a "much larger role" in the new film than Katie Holmes did as the same character.  This can only be to the good.

As for the potential spoilers, the rumor is floating around (and confirmed by good sources) the ether that Cillian Murphy will be reprising his role as the Scarecrow.  Whether that's as a cameo or a full-blown appearance, we shall see.

(Additional info from Batman on Film)