Here are some of the newest Godaddy codes. I just used OK9 to purchase some .com domains and it worked without a problem.

OK7 - 10% Off Anything
OK8 - 20% Off $50 or More
OK9 - 30% off Domain Renewals or New domain registration.

**Special Godaddy Coupon Expires August 31, 2009.
Go Daddy Code OK25 25% Discount on all hosting plans or any order of $91 or more.