It would depend on what bearing. One thing to try would be to remove the serpentine belt and turn the accessories by hand (with the motor off, obviously... LOL) and see if you can hear anything or even feel any drag or resistance on the items. You could also take it by a auto shop and see what the mechanic's opinion could be. It also sounds a little more prominent closer to the alternator.
I don't think I can do ALL of that for my exhaust... bummer.