I followed Iluvmil's excellent advice, went to the parts store, and for under $50 came home with refrigerant (three cans, one including dye), a hose and guage, and a UV penlight to help me spot the leaks. I located a port near the compressor (no cap on it, though) and followed the instructions to charge the system. Within a few minutes, there was cold air coming through the vents, which tells me the compressor works (right?). I figure that there may be additional leaks because of deterioration of rubber seals, in addition to my original condenser leak, but my evaporator should be ok, since it hasn't been under pressure (right?).

Two problems - I took the hose off of the can with the dye before it was empty - big mistake. There's ugly green dye everywhere, so it won't help me spot leaks. Also, I heard the refrigerant leaking from the charging port - is it possible that it is screwed up from being exposed without a cap, and will need to be replaced, or just cleaned?