Help Me!! weird sound in low MPH?

HI,
I've never posted here before, and I sure hope someone will be willing to help me. I've got a 2001 Sentra and its making this awful squeaky-squealing sound. It stops once I accelerate past 20 mph and I haven't heard it while braking. I'd really appreciate it if someone could tell me what is probably making this sound. I don't want to sound like an idiot when I take it to be fixed.
Thanks a lot for any help.

it could be a belt or the brakes

Could be one of a few things. 1: It could be brake dust, which will eventually wear off or you can spray it off with a power washer(car wash) or brake cleaner. 2: if you stopped hard lately, it could be heat glaze built up on the kaliper. It will eventually wear off in a few days. 3: How long have you had the car? Your brake indicator on your wheel might be rubbing your rotor to let you know that you need new brakes.
Good Luck...