I highly recomend Grinderbikes. His conversions are the best way to get started with fixed gear or singlespeed. Jon Grinder built me up a fabulous low-cost fixed gear conversion that I have been riding everyday since January. I ended up with a something very reliable, set up basically exactly how I wanted it (in terms of gears, bar type, brake setup, etc) and I ended up with a really versitile commuter with cool old school name brand components. He's very sincere about getting it set up the way you want and will help you with questions/problems even you've been riding it around for awhile.