The $20 Amazon credit offer has been extended to the Call of Duty: Modern Warfare 2 Hardened Edition (PS3/Xbox 360).

'Modern Warfare 2' Hardened Edition for Xbox 360 includes: game, steel book with metallic finish, art book, game manual and token to download the original 'Call of Duty.'. 

The standard edition also has the $20 credit, while the prestige edition is eligible for a $10 Amazon credit.

Call of Duty: Modern Warfare 2 releases on November 10, 2009, and release day delivery is also available as well!

FYI - Amazon notified us that this offer will be extended to all existing pre-orders.

Check it out:  Amazon - Call of Duty: Modern Warfare 2