Yo,
Technically you need an Impact screwdriver, but it still doesn't work very well...
I used penetrating liquid (aero-croil, some industrial grade shi* my friend gets), let it sit for like a minute, then got one out with just the impact screwdriver, and the other, my bro had to hold force on the screwdriver, then I turned with a pair of pliers...

 

I just drilled mine out. h:

 

1. spray penetrating oil
2. use impact screwdriver and pick the phillips bit that fits in the slot real tight. If the bit doesn't fit tight, the slots will get torn up, then you will have to drill and use a screw extractor bit with a t-handle. You can get a impact screwdriver from sears.
3. hit impact screwdriver with mini sledge hammer.
4. when you reinstall the phillips screws put grease on the threads, then they will come out easy the next time.