Flying Circus WWI Air Rules

Flying Circus is a set of free wargames rules based on the old Avalon Hill Mustangs game.

Fast Play WWII Aerial Combat Rules

Matt Fritz offers a set of fast play miniatures rules for World War II Aerial Combat.

World War I Dioramas

Eye Candy time.

Mike Cooper has photos of several World War I dioramas that he has made. There’s Austrian Artillery, one of the Great War in Palestine, a trench mortar and a gas attack model.

Canvas Eagles WWI Dogfight Rules

Canvas Eagles is a set of free wargames rules for WWI Dogfights

Grand Fleets demo rules

Majestic 12 games has these demo rules for their Grand Fleets miniature wargame. My group has played these and really enjoys them. Majestic 12 explains:

Grand Fleets is a comprehensive miniatures game of dreadnought-era naval warfare. In addition to rules for everything from ships to aeroplanes, Zeppelins to submarines, the rulebook includes:
Data cards for over 120 ships, plus guidelines for converting any ship of the period to game values; Eight scenarios encompassing conflicts from the Sino-Japanese War of 1894 through the opening salvoes of World War Two, including several variants; Fifteen pages of weapon data, covering all major gun and torpedo models in use through 1939, over 200 aeroplanes, and more than 20 airships; and Optional rules for flotillas, night-fighting, smokescreens, and more!