Here's a list of all clubs and schools in Germany:

as a map:
http://www.segelflug.de/karte/d_karte.html

sorted alphabetically:
http://www.segelflug.de/segelflug_de.html

and a list of all sorts of clubs in continental Europe:
http://www.segelflug.de/segelflug_eu.html

Claudia