The DLC comes in the form of Insane Night DLC Pack (coming September 17) and Prey in the Darkness DLC Pack (coming September 24th), the latter is rumored to be PS3 exclusive.
Insane Night DLC Pack consists of the Dem Bone’s Scarecrow Challenge Map Packs and Crime Alley Challenge Maps, both of which were originally thought to be exclusive pack-ins with Gamestop and Collector’s Edition purchases.