edit: problem with the AC compressor Clutch

[futureneck]

hey guys,
I have a question about my 2001 corolla and I figure someone here can surely help. I noticed a noise coming from my belt area bottom front region. I noticed that the cap like piece that holds the belt on is spinning with the belt. Normally it doesnt and sometimes it stops and the noise goes away. It is the pully just under the alternator. I know that I described it pretty poorly but maybe someone will know what im talking about. I could be the belt tensionor because I was noticing that growl that I have read about a few times on here.
Anyway any help would be appreciated
btw is there a website that shows where and what all the parts are on this model. thanks
Adam

OK it seems to be the AC compressor clutch
the air is still working but the part at the end is spinning when it is supposed to be still. Is this problem repairable or is it just that i will have to get a new one?

[Buurin]

The smooth pulley under the alternator is the water pump; tensioner is the other smooth pulley linked to a spring loaded arm. That piece is also known to be noisy though. Both are supposed to spin.

EDIT: Pulled this out of toyodiy.com

[futureneck]

i think it is the cooler compressor
it is part 88403 i think the hub