Below a selection of great websites with info, i will add more later on.
Click on a name to go to that website.

Wehrmacht Awards Forum - My favorite website! perfect for collecting German stuff.
Lexikon-der-wehrmacht - Probably my favorite research website! perfect for unit research.
World War II day by day - Great website with unit build-up info, unit logo┬┤s and more!
Volksbund - German wargrave website, with search function, although not complete its good.
Axis History - Great website on German forces and their allies.
Panzer Archiv Forum - Very good forum about German units and battles, mainly panzer related.
Erkennungsmarken - Good website about German Erkennungsmarken. With many examples.
German tactical symbols - (direct link to) page about German tactical symbols.
Feldgrau - Good German military history research website.
Der erste zug - (direct link to) page with many good articles on the German soldier.