High pitched sound when starting vehicle in the morning?

I was wondering if anyone has had this before. When I start my Taco up in the morning, I get a high pitched screaching sound comeing from somewhere in the engine area. What is causing it?

 

belts...

 

Make sure the belt tensioner is working properly.

Inspect the belt & pulleys, make sure they're clean (don't spray anything on them).

Then - take the belt off and inspect the pulleys for bad bearings.

A squeek can be caused by a belt slipping (not tight enough) or a bearing going bad - a dry squeel and after they warm up, the lubrication inside the bearing flows to quiet them down.