Thanks for all the great info! Clearly the single speed route is easiest and cheapest, but he thinks a fixie is cooler. We don't have time to do it now, but I'll just let him take it to school and do the conversion himself when he's there. It does look pretty straightforward, but I'm not sure its worth the cost of a new rear wheel for this frame. It seems like you can get an already converted bike on ebay for not too much more than the prices of parts to do your own conversion.