We had the same problem with my son's Crossfire. The way we got them off was to raise the car with the jack, so the wheel was just barely off the ground. We then took a 2 inch diameter by 5 foot long pipe, and with a combination swing while dragging it on the driveway to avoid hitting the wheel, we whacked the bottom of the tire (Inside going outward). I expect a 2x4 would work as well. One or two good hits on the tires had them come off.

The wheels had corroded around the center hole. Before putting the wheels back on we cleaned the center holes, and put some anti seize grease around them before re-installing the wheel on the car. That has worked well and we have not had any problems after that.