The Jackson Gamers have this set of free wargamesrules for the English Civil War. They use a card activation system, (not surprising, considering the acknowledged Brom influence), and d6s to resolve actions. These rules are 20 years old and in their 6th edition, so they are well-tested.
Majestic 12 Games has these demo rules for their For the Masses Fantasy miniature wargames system. Here's their blurb:
For The Masses is a complete fantasy mass-combat wargame system. But it is also much more: The flexibility of the system allows players to use any fantasy setting and armies to play out famous fantastical scenarios and ancient epic battles. Several sample army lists are included in the book but the real strength of For the Masses is the unit creation system. This system encourages players to be creative, use their imagination and have fun, which is the way wargaming should be.
A while back I bought a bunch of Wargames Foundry's pirate figures. My idea was to make a bunch of boats and use them to play the Pirates! game from Flagship Games. I got sidetracked while trying to figure out a good way to make the ships. Now, Games Workshop has an article on building 25mm - 28mm boats.
David North has the Hunters In the Sky free wargames rules for WWII and WWI aircraft. There also are printable turning templates and counters for those who don't have miniature airplane figures.
Dave Watson has reviews for 15mm and 25mm wargames figures from various Balkan wars and periods, including WWI, Greek Wars of Independence, Renaissance, WWII, Ancients, WWI Naval, Russo-Turkish War, and Byzantines. Manufacturers listed include Old Glory, Irregular, SHQ, Donnington, Gripping Beast, Foundry, Newline, Brittania and more.
Miniature Wargaming is part of the "adventure games" hobby, which includes r ole p laying and board games. Wargamers recreate battles on the tabletop with toy soldiers, like a more complicated game of chess. Models range in height from 6mm to 28mm tall, with 15mm and 25mm being the most popular. There also is a growing interest in toy soldiers and military models, such as the 1/32 and 1/35 scale plastic soldiers from Conte, and Marx.
The most popular miniature wargames are fantasy and science fiction based, such as Warhammer, Warhammer 40K, Warmachine and The Lord of the Rings. World War II games such as Flames of War and Axis and Allies are new favorites. Other favorite historical periods include Napoleonics, the American Civil War, and ancients, such as Romans or Greeks. Other gamers enjoy miniature naval wargames, recreating battles like Trafalgar, Jutland and the Coral Sea.
Hobbyists research historical periods and paint their tiny soldiers in accurate uniforms. Others develop "historically realistic" rules sets or build scale battlefield terrain using model railroad techniques.
For pictures, visit the gallery.
Some of the bigger hobby companies are Games Workshop, which produces Warhammer, Wargames Foundry and Old Glory Miniatures. Wizards of the Coast produces several lines of pre-painted miniatures games, such as the Star Wars and Dungeons and Dragons miniatures games, and a historical game with pre-painted miniatures: The new Axis and Allies game. Wizkids produces a fantasy collectable miniatures game, such as the Mage Knight and Heroclick fantasy games, the science fiction games MechWarrior and Rocketmen, as well as the quasi-historical Pirates of the Spanish Main.