Here is a list of Discount / Promo codes for Godady (Go Daddy) as of July 2010. Simply order your domain and at the final state of checkout there is a field towards the bottom that says "If you have a promo or source code enter it here:". Simply cut and paste the promo code below into this field.
2010 Codes - just used the first one, YES3 on July 15th 2010 and it worked
For Domains:
QUEEN3 - 30% off .com domain names (works on RENEWALs)
YES3 - 30% off .com domain names
YES1 - 10% off any order
YES2 - $5 off an order of $30 or more
$ Discount by Order Size:
$30 or more : MIN2 - $5 off
$40 or more : YESOFF - $10 off
% Discount by Order Size:
10% Off: MIN1 - any order size
15% Off : YES15 - $75 or more
For Hosting:
YES20 - 20% off a 1yr or greater hosting plan
MIN1 - 10% off a month to month plan
For Auctions:
AUCTION12 - 50% off a subscription
For SSL:
YESSSL - $12.99 SSL account (usually $30)
UK Specific Coupons
For Domains:
QUEEN3 - 30% off .com domain names
% Discount by Order Size:
10% Off: QUEEN1 - any order size
20% Off : UKTOP9 - 35 pounds or more
25% Off : UKTOP251 - 65 pounds or more
Other UK Specific:
FANSSL : 12.99 SSL
FAN20 : 20% Off Hosting