you need to search for "alloy refurbishment" or "powder coaters" in your yellow pages or local book.
I got mine done here in the UK for £50.00 per wheel and what a fantastic job they made. The wheel came back looking brand new and it only took a few hours. The best part is that they can be polished and waxed right away.
My alloys were scuffed bad and had lots of scratches on them but they took them all out includded in the price.