Central European History:
http://journals.cambridge.org/action/displayJournal?jid=CCC

German Historical Institute:
http://www.ghi-dc.org

German Studies Association:
http://www.thegsa.org/

H-German:
http://www.h-net.org/~german/

H-Soz und Kult:    
http://hsozkult.geschichte.hu-berlin.de/index.asp 

Links to German and international archives:
http://www.archivschule.de/content/

The "Nachrichtendienst fuer Historiker":
http://www.nfhdata.de/premium/index.shtml

The KVK:
http://www.ubka.uni-karlsruhe.de/kvk.html
The KVK is an extremely useful "meta-catalog" that allows for simultaneous searching of
several library catalogs, among them the union catalogs for Bavaria, North
Rhine-Westphalia and Southwest Germany. The list of covered catalogs keeps growing; it
now includes Austrian and Swiss libraries, as well as an increasing number of other
national catalogs.

A listing of major online catalogs in Germany:
http://www.grass-gis.de/bibliotheken/kataloge.html 

Academic, public and special libraries (by city) in Germany:
http://www.hbz-nrw.de/produkte_dienstl/germlst/index.html

The German national bibliography online:

http://dnb.ddb.de