A rather overwhelming amount of glutenfrei supplies with imports from the UK (although not always available). So far, the only place I’ve found Xanthan Gum.http://www.meingesundesbrot.de/
As the front page says “Handwerklich gefertigte, gesunde Backwaren und weitere Lebensmittel ohne Gluten, ohne Hefe, ohne Laktose, ohne Soja.”. Thats no Gluten, Yeast, Lactose or Soya!http://www.gutes-glutenfrei.de/
They mostly stock a supply of pre-made supplies of the kind you’d normally find in a supermarket, although a little cheaper.http://www.querfood.de/
Wide selection of items including a good range of Pastas and fresh baked bread.http://www.foodoase.de/
Fairly standard selection of items although they do have a few harder to find freshly baked goods.http://www.alles-glutenfrei.de/
The usual selection of pre-made stuff.
A good selection of pre-made frozen gluten free goods.
Seems to be (at least partially) similar products to foodoase.
A list of gluten free online shops in German.
Blogs and Otherhttp://blog.glutenfrei-kochen.de/
A German blog on living gluten-less. Also check out the parent site if your German is good enough for tips on Glutenfrei cooking.
The main German blog for Celiac disease.
Good German blog on gluten free living.
A list of hotels in Berlin that can accommodate the gluten afflicted.
Good German blog with reviews of products/restaurants/travel etc.
The German celiac society.