+1 on swshawaii's advice. It's a worn belt or bad bearings in the pulleys.
Also, I have found that when coolant gets on it, it can squeak. Knowing all my pulleys and belt were good. I washed it in a bucket filled with water and dawn. Then, rinsed well. My upper rad hose worked it's way loose a had a fine mist of coolant spraying out onto the belt.
If never serviced before. Go ahead and change belt, idler pulley, and entire tensioner assembly. Should be around $60 on Rockauto or Amazon. Gates brand.
+1 on the shorter belt:supercool:
If none of that works. All that's left is the power steering pulley and a/c pulley. (not common) Highly doubt it is the crankshaft pulley.