Could be a wheel bearing, I used to have a chevy that ate wheel bearings, when one failed it made a similar sound. You can check it by lifting the wheel and try to rock the wheel back and forth at 12 and 6 oclock. if it moves at all the bearing is bad.
2002 Ford Focus ZX5 2.0 Zetec MTX
2003 Ford Escape 3.0 Duratec