Its the next to the starbucks opposite Yun Kee restaurant. Its a bit difficult to find, as the only give away is that rotating colorful thingy that all barber shops have. You need to go into the alley and up one floor.
Its kind of cool ... great magazines to read from the UK and they speak fluent english in there.
Also the Mandarin Barber shop used to do cuts for $200 (its in the Mandarin Hotel beauty salon .. ) one of the better kept secrets in Central.