Marcus Reynolds offers Warriors of the Wasteland, a set of skirmish level science fiction rules that he devised when he became tired of the shenanigans of a certain miniatures gaming company who shall remain nameless but whose initials are GW.
The Lord of the Rings Yahoo group has army lists for playing a Aztec v Conquistators variant.
Games Workshop’s Lord of the Rings system proves to be remarkably versatile, as gamers have adapted it to a large number of skirmish periods.
The Vietnam variant of the Legends of the Old West game is available at the Lord of the Rings Battlegame Yahoo Group.
Micro Armor Devastation is a set of fast play miniatures rules for land and air combat from World War II onward. They’re very nicely done in a pdf format.
Jim Wallman offers a set of free naval wargames rules called La Felicissima Armada. It’s a Spanish Armada naval game designed to use 1/144 plastic ships on the floor.