Henry Scherer is the very best. My Contax IIIa now functions perfectly. But he does more than a simple "CLA." He pretty much completely disassembles the camera, cleans everything ultrasonicly, and reassembles the camera over a period of one week. You might find cheaper service, but you will not find better. I dare say you won't even find anyone else his equal. He's also very honest and open.

http://www.zeisscamera.com/