Squeal? Try this...
 

Seems that some folks believe the only way to eliminate a squeal from a pulley is to replace the the pulley. Not so, read on.

Once you've determined which pulley is causing the noise, remove it drom the vehicle.

Start by wiping off the dirt from the race seal.
http://i46.tinypic.com/34oyaev.jpg

Use a small screwdriver to gently pry up the seal. Work it in carefully so you don't damage the seal.
http://i49.tinypic.com/343ht3o.jpg

Carefully remove the plastic ballbearing spacer with the same screwdriver you used previously.
http://i49.tinypic.com/2a4qpnr.jpg

This bearing uses a plastic spacer to keep the ball bearings in the proper location, other bearings may use a none removeable metal spacer.

At this point you can see the old grease is packed around the outer race but there doesn't appear to be any broken ball bearings or metal fragments so a little Brake Parts Cleaner or Carb & Choke Cleaner can be used to clean things up.
http://i46.tinypic.com/oqhbv4.jpg

Repack the race with grease.
http://i47.tinypic.com/of3968.jpg

Reinstall the plastic spacer.
http://i46.tinypic.com/34i06jd.jpg

Reinstall the race seal. Make sure it fits back into the the recess on the outer and inner race.
http://i47.tinypic.com/2uj04m9.jpg


That's it, nice and easy, plus you saved a few bucks...and no more squeal!

The pulley in the pics is from a Chevy belt tensioner but the same process can be used for any pulley that uses sealed ballbearings.