Look at the joints. If it the outer, the stud that goes to the steering knuckle will move. If it's the inner, the ball joint at the inner will show looseness.
I have a Youtube video showing a bad inner.
[video=youtube;D9cFh68Bwho]http://www.youtube.com/watch?v=D9cFh68Bwho[/video]
Here's the process for an outer - not our platform, though.
[video=youtube;ouef7W0riz8]http://www.youtube.com/watch?v=ouef7W0riz8[/video]