Symptoms: Unbearable squeaking and squealing
Once you've got the car jacked up and the tire removed, you're ready to take off the caliper and remove the actual pads. You'll first want to remove the slide pins, which hold the caliper in place. Once these are out, you'll be able to separate the caliper, which will only be hanging by the brake line, then. Don't let it rest only on this line, put it on something or use something to hold it up. You'll be able to remove the actual pads now, which, if the car was squealing, will be heavily worn down.
From here, you'll need a c-clamp, in order to compress the piston back down into the caliper. Be careful with this, and you don't want to push the seal back in unevenly. While everything is apart, this is also a great time to check to see if the worn pads did any damage to the rotors. If you run your finger across the rotor, and you feel deep grooves or uneven and warped surfaces, you're going to want to replace the rotors, as well. Now you're ready to slide the pads back across the rotors, re-insert the brake caliper over the pads and tighten up the pins. The final thing you want to do is check your brake fluid. Not so hard, right?