A good way to check would be to get the front end up in the air and turn the front wheels; if it's a bearing you should be able to tell, but if it's in the driveline you should be able to isolate that as well.

__________________
2001 X5 Sport 3.0/5-speed
1998 318ti/5-speed
1988 735i/5-speed
1984 528e/5-speed (soon to be M20B25-powered 525i!)