The Tyneside Gamers offer a set of World War II skirmish rules. Lots of other rules sets at the page also.
World War Two
World War II Battles In France
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 WWII Naval Rules
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.
Destroyer Commander
Destroyer Commander is a variant for Mongoose Games’ Victory At Sea that focuses on smaller ship actions. I have always wanted to do Destroyer and PT Boat games.
Crush The Fascist Vipers WWII Rules
Crush The Fascist Vipers is a set of free wargames rules for 6mm WWII games.