1) Turn the wheels as far as they will go in the direction of the bulb you are trying to replace.
2) Look on the front side of the wheel well and you will see an oval plastic access cover. Remove it by prying the edges carefully with a large screwdriver.
3) Carefully reach forward through the hole. You need small hands and be careful not to cut your fore arms on the sheet metal. I find it easiest to manipulate if you can reach in with your hand upside down.
4) At some point you should feel a finned piece of plastic that is the backside of the bulb holder.
5) Twist the fin about a quarter-turn counterclockwise and pull it carefully out.
6) If the bulb falls out of the holder and down into the housing as you are pulling it out, curse like a sailor.
6a) If the bulb has fallen out and into the headlight, get a shop vac with the crevice tool attached and a piece of half inch PVC pipe about 18 inches long. Put the pipe inside the crevice tool and turn on the vacuum. Slowly move the PVC piece into the headlight access hole and down into the headlight assembly. Allow the suction to pick up the bulb (you can view your progress through the headlight). Slowly and carefully withdraw the PVC pipe from the headlight assembly, and the bulb should be suctioned to the end of the pipe. If it falls out try again, you will eventually get it.
7) Remove the old bulb by pulling it out of the holder.
8) Remove any tarnish on the contacts with emery paper or a small file. Coat the contacts of the new bulb with dielectric grease to help prevent corrosion and insert into bulb holder.
9) Carefully insert the bulb holder with the new bulb into the housing. You will have to feel where the plastic tabs engage the housing. Give it a quarter-turn clockwise to lock it in place.
10) Pull gently on the fin to see that it is locked in place.
11) Push the plastic access cover back into place until it snaps in. Ensure that it is securely in place by gently trying to lift the edge. If it falls out too easily it won't stay in place as you are driving. This piece has a tendency to distort with age, and it may not snap securely. You can either purchase a new oval access cover (VW Part Number: 3B0809967 approx. $15 at 1stvwparts.com ), or you can simply split a piece of duct tape and fold it over the entire edge of the snap feature on the back of the cover. This makes it thicker, so that the plastic on the wheel well is better able to hold it.
12) Tutto Fatto.