Larry,
You know, it's a shame we don't have a specific forum for technical questions like these. Hell, maybe we could even have a couple of them - one specifically monitored by an 'expert' of sorts.
I would just have the brakes looked at. Your caliper could be sticking, or it could just be the wear indicators, as mattski suggested. If it's the latter, then your pads are just badly worn. If it's the former, then some mechanical problem is causing the pads to remain forcefully against the rotor, wearing them rapidly. Either way, that squealing is probably an indicator that your pads are nearing the end of their useful lives.
Amanda, just because it happens when you're not braking doesn't mean it's not your brakes. There are plenty of noises that occur when the brakes are not applied. The pads pretty much ride right on the rotors, so any number of noises can be caused by rotor warpage, caliper problems, etc. My wife's Legacy made horrible noises from the right rear while turning. One look at the pads in the right rear showed me that a sticking caliper had caused the inner pad to wear past the friction material, right down to the metal.