First bit of Batman: Arkham Asylum DLC will be Insane Knight
Mike Kebby, from SCEE's PlayStation Store Team, has posted on the EU PS Blog that the upcoming DLC for Batman: Arkham Asylum landing on September 17 will be Insane Knight.
The other bit of DLC, Prey in the Darkness, will land on September 24.
This confirms rumors from earlier in the week.
You can find Kebby's response to DLC content for the game in the comments section through the link.