do i need wheel bearings

lately i have noticed an unusual hum coming from the front of the car,it doesnt seem to go with the speed of the engine,i changed the front tires to a smoother set and still the noise is there,it seems to stop for a few seconds when the brakes are applied.....is this the symptoms that lead up to failing wheel bearings, is it a tough job,and what replacments are reccomended....thanks

newscarver
Try this thread,
http://www.automotiveforums.com/vbulletin/showthread.php?t=374666&highlight=bearings