Richard Bradley offers a set of free wargames rules for World War II Skirmishes.
Rules: WWII
Pz8 Coastal Rules
Pz8 is a series of two-page wargames rules. Among them are is a set of free wargames rules for coastal actions.
WWII Platoon Commander
WWII Platoon Commander applies the mechanics of the Blitzkrieg Commander rules to a skirmish system.
De Belli Mundi Secundus World War II DBA Variant
Damond Crump offers a WWII Variant for DBA.
Battle of Britain Rules
Battle of Britain is a set of free wargames rules for operational level games. The authors write:
This is a fast playing operational level game about the German air raids over England on August 8th, 1940. Designed for group or convention play where players are in charge of the various sectors or Luftwaffe raids and it can be completed in a few hours. This PDF includes the rules, a map, markers, cards, and aditional materials needed to play the game.