Yesterday, Warner Brothers and Monolith Productions (No One Lives Forever, F.E.A.R.) announced Gotham City Impostors, a downloadable title for PC, PSN and XBLA that is supposed to be released later this year. In the game you won't actually control the caped crusader, instead you'll sign up for the teams Team Bats or Team Jokerz (no Team Edward, sorry Bengt) - two militias that have formed to make Gotham a safer place. Or less safe, I suppose. Then you duke it out in what sounds a bit like Team Fortress.
You're supposed to be able to customize your own character and unlock new equipment and other fun stuff as you play. We'll get your more details about the game when we have them.