Sounds like a belt or it could be the sealed bearing in the idler pully , Mine went out a few months ago and screamed pretty loud.
But the whole clutch in thing worries me . My throw out bearing went out at the Fall crawl and there was no mistaking it
it was loud !!!
Take a very long screw driver or pry bar and have someone give the Jeep some RPM's and use the screw driver / prybar like a stethascope ( SP? ) , put it on the alt. body , idler mount, water pump ..... put the handle in your ear. you will be able to locate the area the sound is coming from.