If the belt is sqealing then go buy a new one... If it still does it you should check the water pump, alternator, or power steering pump, and see if they are sqealing... I don't think that getting a belt wet would cause it to make noise, or at least it never has for me.

I think I may have gotten degreeser on it the belt stoped squeaking after like 6 hrs of running time (constitly squealing)