You can use a pair of Vice-grips if the bolt is stripped out so bad that nothing gets traction on it. It is a major bitch because you won't have much leverage, but it's worth a shot. It worked for me once.
getcha a 3" steel pole about five foot long and place the handle of your four-way (assuming that you are using a four way lug wrench) into one end and you should have plenty of leverage to break it loose.
this is refered to as a 'cheater' and it works great.