Rear Wheel Bearing

[Mayszak, David A]

I'm getting a "howling" sound from the right rear of my car.  It definitely
is wheel/tire related and starts at about 40 mph.  I suspect passenger side
wheel bearing.  My questions are; Could the problem be something
else...axle???  Is there a way to definitively determine if it is indeed the
bearing??  If it is the axle, I'm inclined to taking the bearing housing out
and bringing it to a machine shop to have a new bearing pressed in,...I'm
told this is a fairly easy job to remove the bearing housing, anything I
need to be concerned with when doing this???   Thanks for you help.