-PB Blaster...as mentioned -hand held impact wrench (the kind you hammer and it reverses) -torch (hand held propane) -drill -dremel tool with small grinding disc
While some are saying to try and save the bolt/screw...sorry, but if its badly rusted and pitted or a stripped head, do whatever you can to get it out and replace it with something new. Because odds are you'll be taking it back off again sometime in the near future and you'll be back down this same alley again...
