Car makes a whistling or perhaps whining noise.

Car makes a whistling or perhaps whining noise that seems to be coming from the passenger side, maybe towards the front. This noise is related to movement of the car (it is present when coasting down a hill while at low RPMs). It happens after the car has been driven for 5 to 10 minutes. It is only heard at speeds at or above about 20mph. Noise itself is not jet engine loud but when radio is off, you definitely hear it.