To request a free Minecraft avatar item simply go to the website and enter your USA address details - you just need a zip code from one of 3 states ;-)
They will then email you a code for either a Dog or Pig head.
Sample Zip Codes For You To Use:
Idaho (ID): 83701
Oregon (OR): 97201
Codes must be redeemed by September 30, 2012
Completing the form the first time will give you a code in an E-mail for the Pig mask. Completing it again, using the same exact details will give you a code in an E-mail for the Cow mask.
There is no Dog mask.
The promotion has ended. All codes which have been given out will expire in a month if not claimed (30th September)