Pete's method sounds good - I've used it twice in the past - especially note the idea of putting the figure on a cloth or something to protect the face-down front part.
2 other methods I know of:
1) Use a very small drill bit and drill the screw. I tried it once, skeptically, but the screw head came off no problem, I slipped off the back piece and then I used pliers to take out the screw part. Seemed risky at the time, but it worked out great for me. I only recommend it if you could stand to damage the one part. In my case only the screw was ruined, and it was obviously stripped to begin with.
2) Put super glue on a crappy screw driver and attach it to the screw. Let it dry and then give it a go again. Never tried it personally, but someone on another board reported success.
Good luck - and I'd love to hear what works for you guys!
