Bad news. That iPad you were going to buy tomorrow? It's going to cost you twice as much. Why? You'll need at least two iPads to play some co-op Nazi Zombie's for the device in HD. Activision has created a special version of the iPod/iPhone version of the game specifically designed for the iPad's high resolution screen, and it'll be available at launch.
Call of Duty: World at War Zombies will run you $14.99 - though it's unclear if it includes the recent map update or not.
The game seems to be the only co-op title launching with the iPad. Brothers in Arms 2 and Eliminate will both function on the device, but aren't offering special version enhanced for the larger screen.