Matt Fritz offers a free set of miniatures rules for playing games involving B17 bomber runs over Germany in World War II. Looks like fun.
Rules: WWII
High Seas Drifter WWII Era Battleship Rules
High Seas Drifter is a set of free wargames rules for playing battleship combats in the World War II era.
Midway Dice Game
Midway is a two player game about the classic naval battle using flowcharts instead of maps.
Road To Hell WWII Skirmish Rules
Road to Hell is a set of free wargames rules for WWII skirmishes. The author writes:
1.0 SCALE
This is a skirmish game so one miniature represents one man and one model vehicle is one vehicle. One centimetre corresponds to around 2 metres and a turn represents 10-20 seconds of real time.
2.0 YOU WILL NEED…
You’ll need a couple of units or squads (one per player) of around 8-15 miniatures each to play Road to Hell (for more details see the Army lists), a few six-sided dice (hereafter referred to as d6) a ruler or tape-measure (all measurements are in cm) and a minimum recommended playing area that measure 80x80cm (30×30 inches) for 28mm figures and 60x60cm (2×2 feet) for 20mm figures. Considering that these are small skirmishes, scenery is very important. Avoid battles in open ground as they will be very lethal and not particularly satisfying
Fire! Ogon! Feuer! WWII Skirmish Rules
Fire! Ogon! Feuer! is a set of free wargames rules for World War II Skirmishes. The author writes:
These rules are designed for use by both beginners and veteran players. Play can be quick and easy OR made more realistic and slower by adding advanced options.
Combat during World War II focused on volume of fire into a specific area combined with rapid movement of combat units. The weapon systems were poor by modern standards and there was a constant design battle between shell penetration versus vehicle armor.