Next time, use more penetrating oil before you start on the suspension work...ironpig said:
That said, you will probably need to use one of those 'nut cracker' things. It is pretty much a blade that bites into the nut and splits it, allowing you to pull it off. The other option is possibly an impact gun if you can get it in there, or some heat (after some more penetrating lube). If I remember right, there is also a bit of a place to grab near the rubber boot that you might be able to get needle-nose vice-grips on or something...
-Charlie