Eidos and Warner have announced that The Joker will appear as a free downloadable character for the PlayStation 3 version of Batman: Arkham Asylum. He'll be playable on the game's "challenge maps." There aren't a lot of details out there about how he'll play or anything, but they did release this image to go with it...
Yup. That's the Joker, all right. Look for the game in stores on June 23.