if you are wandering around north central Phx, Quiltz and Modern Quilting are both near Paradise Valley Mall . Quiltz is at Thunderbird and 40th Street. Modern Quiling is at Cactus and 45th Street.
I agree with 3 Dudes and SAS. SAS is a 'poke around and see what you can find' kind of place. Darn if my car doesn't go RIGHT by there if I need to take someone to the airport!! The Indian School location has a good selection of quilting cottons. Be prepared to dig around.