Imagine Image offers the freeHex Command Ancients Rules for miniatures wargames. The hex system is supposed to simplify things and speed play. You can play without a hex board if you want.
Net Epic is a set of free wargames rules based on the old Games Workshop Second Edition Space Marine.
This Yahoo group has free wargames rules for recreating battles of the Indian Wars in the Old Northwest: the French and Indian War through the Blackhawk War.
Mike Schubert of the Pretoria Wargames Club has an article on which Essex miniature wargaming figures to use to build armies of obscure near eastern bronze age armies, such as the Mitannians, Canaanites, Later Hebrews and Neo-Hittites.
Jim Wallman’s Little Lambent Meteors is a set of free wargames rules for 18th Century riots, using 15mm figures.