The Tyneside Gamers offer a set of World War II skirmish rules. Lots of other rules sets at the page also.
Battles in France is a set of free wargames rules for platoon operations in World War II. The author writes:
WWII Battles in France covers two distinct battles; the fighting in France and southern Belgium in May of 1940 and the fighting in Normandy, France during July of 1944. Each player assumes the role of a battalion commander with two or more companies under their command.. The game is designed for one or two players per side with 250 build points . a side if defending, 375 points if a meeting engagement and 500 points if attacking.
Seas of Lead is a set of free wargames rules for World War II Naval games. Along with the rules are some good looking unit data cards that they made using the Magic Set Editor.