Modern Warfare

Here is new info on how to download content for your xbox 360 for Call Of Duty Modern Warfare 3

“In order to download the new maps you must be an ELITE Premium member. You can become a Premium member by purchasing a subscription through the in-game store or console application.

1. Launch MW3 on the Xbox 360.
2. From the Main Menu, select Multiplayer.
3. From the Multiplayer Menu, select Store (notice NEW is listed for Premium users).
4: The Store screen will feature different options based on whether you are currently an ELITE Premium member or not.

• ELITE Premium subscriber – ELITE premium users will see both ELITE Drop maps (Liberation and Piazza) listed as downloads with the cost shown as Free (0 Microsoft Points).  You will need to download both maps, otherwise you will encounter error messages directing you to download the missing map when trying to play them anywhere other than MP Private Match.
• Non-Premium – Non-premium users will be directed to the current MW3 retail store when Store is selected, where they can continue to download trailers, avatar items, and picture packs.

5: Verify that the transaction price for the ELITE Drop maps is zero Microsoft Points, and select Confirm Purchase.
6: Select OK and Exit MW3 to allow the multiplayer maps to download.”

Source: http://www.blog4modernwarfare3.com/2012/01/26/how-to-download-cod-mw3-dlc-map-packs-and-content-drops/