The noise you mention doesn't sound familiar, especially if you have rear disk brakes. I would get the pads checked out asap which may be very worn and loose in the caliper. (causing the noise??) Rear pads can be changed in about 20 minutes, although you'll probably also want to get the rotors turned. ($8-$10/side) My rear pads lasted for well over 50K and still had plenty of wear left on them when I replaced them. If you say the rear brakes make noise when sitting still, I guess that's if you push on the brake. How about the hand brake? (Shouid make same noise) Sounds like something is loose, or possibly cracked?