Ancient Battlefields is a set of free wargames rules "with an emphasis on Command and Control". The game is over when the opposing general flees the field.
The Illustrated History of the Roman Empire website is just that — a neat historical site with loads of pictures and interactive map. There is lots of fodder here for historical wargamers.
Tom’s Ancient Warfare Rules is a set of free wargames rules for the ancient period.
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.
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.