1. Check the fluid level in the power steering reservoir.
2. remove the serpentine belt and check the water pump pulley. It should have very little play in any direction, and should turn freely.
3. check the little idler pulley by spinning it and listening for bearing noise.
4. do the same with the tensioner pulley.

I do not think the AC clutch is involved, but I was wrong at least one time in the past, although I can't remember when that was.