Take a look at this site,hope it helps.

http://www.visits-to-germany.com/pages/1087.htm

Try these as well.

http://www.kleincamp.de/
http://www.camping-germany.de/

Hers another just setting up I believe.

http://www.worldcupcamping.de

I lived in Germany for 8 years, there are camp-sites all over the place, mainly in the more touristy areas. On the whole they tend to be very well run and set out. We never booked , just turned up. They do have " quiet times" normally early afternoon, when you can't drive in or out or use your car.