Belt Squeaking/Chirping - HELP

[AHughes]

I have a 1997 Mustang (V-6 with 58,000 miles) and recently started hearing a squeaking/chirping noise coming from the belt area. It sounded like the water pump pulley so we replaced the water pump. That didn't fix it. Then we thought it was the tensioner pulley, replaced the entire tensioner, that didn't fix it. We then replaced the idler pulley, that wasn't it. We replaced the belt itself, no luck. We started the car without the belt on -- no noise. With a stethascope, the sound seems to be coming from the water pump area but since we put a new water pump on, we don't think that's the problem. Anyone have any clues as to what it could be? It is very loud and people are staring at me at stop lights. Plus, I'm tired of replacing parts that aren't broken. Any leads, additional information, or websites I should look at would help greatly.