NACA isn't credit score driven, but you must have a good payment history over the last 12-24 months. However, they will work with you to clean up your credit so you can buy. Its a great program offering 30 yr fixed rate, no down payment, no closing costs, and I believe the rate is 4.65% right now.
This program isnt just on your credit. Let me know if you want me to
get you more information. This is a great way to buy a home.