How hard is it to replace the front brake on a 2002 Chevy S-10?

It is not hard at all and it does not take long either. It is easier and cheaper to do them at home than have a dealership do them.

rotors and pads, shouldn't take more than an hour... Tools needed is a 3/8 socket wrench and a 10mm socket to remove the caliber from the rotor, before replacing the old brake pads, take 2 pri-bars (or something that will fit in between the shoes)and use a push/pull method to push the caliber sleeve back flush with the caliber if you don't have a brake tool.