Activision today officially announced Call of Duty: World at War, a new first person shooter sequel in the works at Treyarch Invention, the studio which developed Call of Duty 2: Big Red One and Call of Duty 3. Call of Duty: World at War will take place in the Pacific theatre (and partially in Russia's advance into Berlin). For the first time in Call of Duty's campaign 4-player co-op is supported over Xbox Live - and it supports meta game perks as in CoD4's online mode. Scheduled to hit the store shelves this fall, Call of Duty: World at War will be available for PC, Xbox 360, PS3 and Wii (press 'read more' for details). A trailer is now available.