2001 Jetta TDI A/C problem

[nmudd]

I have a 2001 Jetta TDI with about 125K miles on it. Recently the A/C stopped working completely. The compressor will not kick on at all and when I turn on the air conditioner there is a slight hiss that comes from the vent but no odor and no cool air. I've never had a single problem with the A/C on this car and there were no symptoms prior to the recent total failure. Any ideas what might be causing it and how I might troubleshoot the problem? I'm trying to avoid spending major dollars fixing it since the summer is almost over and we are going to trade it in this winter.
Thanks,
Nick