What might be the cause of a squeeking sound coming from the rear end

brakes, wheel bearings, worn suspension bushings. Need more info to give accurate info

only hear it when I am driving 25 MPH or more..

Could also be a U-joint, does it do this backing up too? Does it feel as if your rotors are warped, could be a brake sqeek at 25mph+

does it change when the brakes are applied?

it sounds like ur differential or rear main seal...does it get louder as u go faster? and do u have any aftermarket parts in the drivetrain, like a new diff or driveshaft

does not get louder at all..when I hit the brakes it quits which makes me think it is the indicators on the brakes.. no aftermarket parts are on the car at all