Heads up for international users purchasing the Variety Map Pack for the PS3. The Variety Map Pack is Region Locked, which means that you MUST purchase the version of the map pack which is compatible with the version of the Call of Duty 4: Modern Warfare game disc that you have.
If you have the GERMAN version of the game, you MUST purchase the GERMAN version of the map pack.
If you have the UK version of the game, you MUST purchase the UK version of the map pack.
More through the link. The pack's releasing for PS3 today, so make sure you check that post before you buy, just in case.