I think the power steering pump is going.

When I am not pressing down on the gas, or turning the steering wheel while not in motion, it makes a loud whirring/whinning noise. Also it becomes very hard to turn, infact I don't force it to turn I just apply some gas and the steering wheel turns as the gas moves. This usually only happens when I'm going very slowly or not moving, which only adds to the "FUN" of parking your car.

I had a friend who was riding with me and when he heard it he also thought it was the steering pump before I even said anything.

So the question is, is that the problem? If so, how do I replace the pump? (if someone could link me to some guide of step-guide I could follow) and does anyone suggest a particular pump or will just any from auto-zone or pepboys do.