I've gotten good service and repair from Garry's Camera Repair in Illinois. Quick turnaround, very reasonable prices, and he's done a number or repairs, both minor and not so minor.

http://www.garryscamera.com/

I've also had very good service from KEH in Atlanta. Very reputable company, good service and repair, not as inexpensive as Garry's.

http://www.keh.com/repair-center.aspx