Chances are it could be a wheel hub bearing. Ensure that your tires are in good condition, cord seperation has been known to make a pretty nasty noise. You can swap suspect tire to a different spot and see if the noise moves with it if so it's the tire. If not check the hub bearings. The is also a bearing on the right side half axle shaft (hanger bearing). These are known to go bad. Determine which one is is and replace.
Chris
February 2009