Sacrifice an X-Acto blade by just filing the tip flat enough to turn the screw - it doesn't take much. (you might want to file the edge a bit to make this a safer operation.) I find it works wonders for those screws too small for the screwdrivers I have at hand. Back the screws out but don't remove them if you want to be able to put the thing back together.. those little devils run away quite frequently if allowed to roam.
Originally Posted by BetterSense
The thread Bethe suggested has a lot of collected wisdom on this subject. The camera is usually worth the effort. Good luck.