Sub Categories:

Offers information on classifications, grapes, A.P. numbers, and regions, including maps. From a UK-based importer and retailer.
German Wine Information Bureau
Provides information on wines, regions, travel, wineries, importers as well as food and wine pairings.
A site for the German wine lover, with tasting notes, vintage reports, reference information and photos.
Short Guide to German Wines
Schlossadler, a US importer, provides this overview of the regions and the grape varieties.
A portal to leading wineries, providing general information as well as point-of-sale material to the trade.