My compressor still works just fine, but the bearing on the pulley is shot, and squeeks very loudly. I just had to have my clutch master and slave cylinders replaced for $700, so I really can't afford to replace the entire compressor right now.

Let's say that I'm semi-mechanically inclined when it comes to working on cars.

How difficult is it to just replace the bearing on the pulley? Where can I even buy just the bearing?

 

LS1 car I assume? You didn't specify - no sig.

The AC compressor pulley and bearing isn't too difficult. You can do it in the car without discharging the system. Remove the clutch center bolt, and then the plate. There should be a snap-ring on the inside of the bearing that needs to be removed. If you have a hard time accessing it, you can unbolt the compressor from the bracket and let it hang (carefully) by the AC lines - no need to disconnect. With the snap-ring removed you can either use a special puller tool, or you can gently pry with a screwdriver and tap with a small ballpeen hammer around the pulley to remove it from the compressor. That inner race is a very slight interference fit.

You sure it's not one of the idler pullies near the compressor? They're notorious for failing and causing noise.