I just replaced my upper right ball joint last weekend.  Took about 2 
hours total.  The biggest problem was ordering the $143 ball joint from 
the dealer.  Yup, 143 bucks.  Sunday, after I finished installing it I 
found the ball joints in the JC Whitney catalog for about $15.  Oh well, 
I guess maybe the genuine VW part was worth it.  Also, I did not have to 
open the brake lines to replace the joint.  Here is what I did:

1. Remove the wheel.  
2. Remove the big 24mm nut on the bottom of the joint.
3. Remove the brake caliper by removing the 2 19 mm bolts.
4. Remove the 2 allen bolts on the top of the ball joint.  
5. Pound (gently) the control arm up (this it the arm that the 
   top of the ball joint bolts to.
6. Pound the ball joint out from below (seems like some kind of 
   puller would have been easier).  
7. Reassemble in opposite order.  

P.S. my old ball joint had maybe 2-3 mm of play in it.

John Brown
jlbrown@u.washington.edu