I can’t keep up with all the coupon codes, so the easiest thing is to just go directly to the following site. You can also find threads on the various domain forums that keep people updated on the codes.

Coupon sites:

DNCoupons.com

Ongoing Discussion Forum Threads

NamePros “You are subscribed to this thread In Light of The End of the Godaddy Loophole…Promotional Codes” Thread

Godaddy promo codes for 2007