I agree w/ the belt being the probable culprit. While it is squeaking, spritz the belt with a little Windex. If it stops squeaking for a moment or so before resuming, you have your culprit...the belt! Try to find a Gates and avoid the Chinese crap...Unless, of course, you LIKE the sqeaking!
If the belt isn't "IT", get back and we'll try something else.
P.