You have to use a very small Phillips head, or rather, one that has a very sharp definted "T" at the head. The kit that finally worked for me (I went through a bunch of different drivers to find one that worked) was this one, from Husky:
The correct bit that I use (works pefectly) is the one that says "PH.1 1/6"
I purchased this kit at Lowe's, but you can order it on Amazon. The worst thing to do would be to completely strip the screw, and then be unable to unscrew the port door completely. PLEASE - get the right driver first, don't strip it.
ALSO - for the MacBook and MacBook Pro - I found a really REALLY great driver for that: The "General No. 744, 4-in-1 Mini" here: