Yea. Like serum said. Grind a slot across the head and use a flat head screw driver to get it out. I use a cut off wheel in a dremmel and it works perfectly.
Another solution I found is just to get a very high quality ground/hardened tip hex wrench and try that. Alot of times the stanadrd hex keys are a little rounded and the hex hole in the screw is a little rounded and that prevents you from getting the screw loose. The very sharp corners of a hardened/ground hex key will sometimes let you get enough bite in the worn out screw to get it loose.
http://www2.towerhobbies.com/cgi-bin...?&I=LXBN25&P=0
Something like these are a good investment over the long run. And a quality wrench usually helps avoid stripped screw heads.
Also, if you have any thread lock on it, heat it up a little before trying to losen it. The thread lock softens and becomes easer to break when its hot.