VW dealers still have them available. I have bought 2 in recent years.
$135.00 each, if you can find a dealer who will give you a break on the
price. Although, with the declining dollar, they may be priced higher now.

Other online suppliers also have them - I have seen them listed on
volkscafe.com - the other list suppliers probably have them, too.

For the amount of effort involved in replacing the sender, I would not
recommend a used one, as they are prone to corroding at the nipple that is
welded (soldered?) on the outside. Buy a new one and be good for another
10 years or so.

Michael

http://www.velocity.net/~vickrail/moshevw.htm