I just went through this on my car. Check the fuse, then if the fuse is good, take out the motor and get a battery charger. Hook it up to the terminal on the wiper motor. If it turns, the key switch is the problem, if it doesn't it's the motor. Also, make sure the arms didn't fall off the motor.
Wow. My first opportunity to depart wisdom on this site. I thought the day would never come. I also had wiper problems (see my post around 6/18 for great advice).
My wipers worked and then stopped working. What I learned was:
(1) Check the fuse
(2) If fuse looks ok, unplug the wiring harness from the wiper switch under your dash. Run a wire from the fuse box to the wiper motor. If the wipes work, you have a switch problem (which is what I had).
I had a hard time finding a 65 switch from a supplier. The ones I did find were $45-$65. I posted a parts wanted ad in the appropriate section of VMF and received more than one offer to sell me a used one for $10.
$10 later I had working wipers thanks to VMF! Do a search under wipers and look for the excellent replies to my post (around 6/18/03).