We previewed this for you last night and it turns out the deal is even broader than we expected.
Consumers in the U.S. that purchase any new Windows Phone 7 from December 17, 2010 – December 31, 2010 are eligible to receive one free Xbox 360 console game. Consumers may purchase any Windows Phone 7 device from any retailer. Consumers can select one of the following games: Halo: Reach, Fable III, KinectTM Joy Ride* and Kinectimals*. Limit one free game per mobile phone number.
So you can get the phone from anywhere, not just brick and mortar stores. Better yet, if you get a BOGO deal you can combine it with this and get 2 free games. That’s sweet! Unfortunately, it is not retroactive. It takes 6-8 weeks to have the game shipped which you redeem from www.myfreexbox360game.com. You can check out all of the details here.