In reply to balmybaldwin:
A variation on the jacking up the other side of the car scheme is this -Get an old short sling and thread it through one of the holes at the top of the wheel. Jack up the other side. Take a strong bar (scaffold pole, jumping bar or similar, but at least 5 feet long) and feed it through the sling and rest it against the ground and the rim. If it's a pretty wheel, a bit of ply and cloth to protect the rim is prudent. For heaven's sake make sure the wheel nuts are still on but loose enough to allow the wheel to move. Then heave, or if the bar is stiff enough and you have an assistant hit the bar (said assistant can also hit the wheel too). Bear in mind that when it goes, the bar will go with it.
If it's really not happening, go to Staples or somewhere and get a can of compressed air (used for blowing dust out of keyboards).
Wear gloves and discharge the whole thing onto the wheel in one go, which will freeze it - and pull as above. It helps if you can get some heat into the disc and hub first - but obviously you can't do that - the easiest way then is to drive, heat the wheel up, loosen the bolts, freeze and drive in a circle