You can google your way to far more than I can assemble here. But here's some starting ideas. First, try the local flea market at the Skyview Drive-In theater off Soquel near the Hwy 1 interchange on Saturday or Sunday. If you're shopping for a used film camera, remember that the two big points are (1.) it does not use a battery to hold the shutter open, and (2) the light meter isn't needed, so broken light meter cameras can be a great deal.
AstroMart is the premier place for amateur astronomers who want to trade equipment; photographic or otherwise.
Cameta Camera is a good place to look for used cameras. The latest postings were retrieved by Astro 9'er Jay F and I've posted it here (fresh as of Sept 10, 2007)