To redeem in other parts of the world:
1) Create an Outlook.com email. Set the region to China.
2) Go to Xbox.com. Set the region to China. Make a new account.
3) Go here:
4) Purchase the game for free.
5) Add address details (Google Maps is your friend).
6) ACIII GoD is now on your account. Log out of Xbox.com on PC.
7) Download the new profile to your Xbox 360.
8) Go to downloads and select the ACIII GoD.
Note: Google Chrome's translate feature works very well with Chinese -> English.
Edit: For those who are already have ACIII on the new account, but can't get it downloaded:
when your download approaches 75% go here:
PLEASE STOP ASKING HOW TO DO IT. THE DEAL DONE DIED. THANK YOU.
Getting payment required pop-up?
Make your xbox account region to china!
Someone should write a tutorial for the XBOX account portion for those who are unfamiliar with their XBOX.
2:15 PST - AC3 full game download gone - possibly dead
The game is no longer for purchase on the site. See OP's link: http://slickdeals.net/?sdtid=5937326&