Alot of auto parts stores sell spray paint specifically for wheels. Google Wheel Painting and theres a bunch of stuff about brands and ways to do it. I used Krylon High Temp BBQ paint for a satin black finish. I've also heard of a few people that used appliance enamel with good results. Just depends on what color you want. As with most painting, its all in the prep. Degrease, clean, scuff, clean, self etching primer, and paint away.