U look in the trunk on either side side along the plastic trim and there will be a circular cutout on either side. U just pop those off.
Next, look inside (flashlight helps) and there will be this screw with a rotating black piece of plastic on it and unscrew the plastic retainer.
Now i highly recommend a plunger! With a plunger, use it to press against the lense and then when u have suction, just pull. Depending on how old the car is, you may need to put more effort in it.
Next, the light bulb's socket needs a quarter turn and it pulls out. If the metal inside is corroded, then you should get a new connector from the dealer otherwise it will cause the new bulb to die in less than a week and you'll need a new bulb. That happened to me :( Its about $3-12 depending on where you get it.
The bulb is a double fillament bulb, and usually, the brake filament goes first and you will still have some light left if the headlights are one.
They say installation is the reverse of removal as is the case here, but u wont need use the plunger here. Just be sure to stick the long screw back through the hole so you can twist the retainer back down on it.
Source: HOW TO w/ pics= http://newbeetle.org/forums/technical-h
o... and BULB GUIDE= http://newbeetle.org/forums/technical-h