Tanks from all countries of World War II

AFV NEWS - Tanks & Armor Page: A number of very good articles on tanks, and home of the AFV News periodical
Battle Tanks: A few interesting articles about World War II tanks
Panzertruppen: Information in French about the tanks and armoured units during World War II
Tank Net: Forum about armoured warfare (as well as warfare in general, and scale modeling)
TANKS!: An excellent reference for information about the development of armoured vehicles for especially minor nations
World War II Vehicles and Advanced Squad Leader: Information about the armoured vehicles of World War II, and details for the Advanced Squad Leader wargame
WW2 ARMOR (World War 2 Armored Forces): Good website, with information on the tanks of all the major combattants of World War II
WWII in Europe: Information and statistics about the European theater of operations