Rear Wheel Bearings on 99

My cougar has been making a roaring/grinding sound coming from the back of the car thati s getting bad enough that something needs to be done. I'm assuming it's a wheel bearing in one or both of the rear tires. The wheel would "grab" when spun, but there didn't seem to be any problems with the rotor. I didn't see if the wheel was loose, which I should have checked. Anyways I've never had the fun of changing a wheel bearing before. Has anyone had any experience changing the rear ones and how bad is it to do? Any help would be appreciated!

Tony

need help on this issue as well