The throwout bearing only spins when you step down on the clutch pedal so if you've got a screech that only happens with the clutch pedal down, odds are very good it's the throwout bearing causing it.
An entire clutch kit from Luk (OE manufacturer of the clutch and throwout bearing) is only $159 from Dial-A-Clutch - Your LuK Clutch Kit Specialist
so I'd replace the clutch too while you're in there. For $159, you get the throwout bearing, clutch disk, pressure plate, pilot bearing, and pilot shaft.
Replacing a clutch and throwout bearing is not a technically challenging job. Unbolt the transmission/transfer case from the engine and lower it to the ground with a jack. It is an unbolt/bolt it back in operation that can be done in 4-5 hours with simple basic hand tools.
Here's how... 1997 Jeep TJ Clutch Replacement