Click here for a collection of links, incl. dictionaries, publishers, hosted by L. Hoffmann (Dortmund) or this one at the Linguistik Server in Essen. A referenced collections of links to webpages and publications online can be found at INTUTE. A link to the Internationale Vereinigung fuer Germanistik is here IVG. Wini Davies (firstname.lastname@example.org) is our UK contact.
Have a look at the fantastic Atlas zur deutschen Alltagssprache (zum Mitmachen!) based at Stephan Elspass's home at the University of Augsburg. Also, look at the Exeter University's German dialects page which has a very full listing of links for the various German dialects, and have a look at the Deutscher Sprachatlas in Marburg.
An archive of texts and a bibliography on Sprachpolitik in Schleswig-Holstein in the 19th century can be found here.
From the website of Virtual Dutch (http://www.dutch.ac.uk/) you can access two
online Dutch grammars, one for beginners and one for advanced students. They
have recently been updated and provided with self-check exercises. You can also
access them directly on:
Cosmas-Corpus at the Institut fuer deutsche Sprache, Mannheim
German Parole Corpus at the Oxford Text Archive
DaF-Portal with exercises and tests online
deutsch-online.com - Austrian Portal for DaF with resources for learning German
Here is the link to our very own Martin Durrell's collection of newspaper texts from the German-speaking areas from 1650-1800 (hosted by the Oxford Text Archive, type '2537' in the Quick Search field to get to the corpus).
For those interested in really old stuff, check out Mediaevum.de, which includes old texts, plenty of historical dictionaries and the invaluable medieval font (supplied by Hamm, Kiel)