This is the homepage of the Napoleonic Strategy Battle Game. You can download the rules from here, and the site will always feature the most recent version of the rules. (Version 1.2 at the moment.)
The rules are divided into three documents, with the first containing the rules for gameplay and the others the individual profiles. The profile rules are complete for Britain and France, but the Russian, Spanish, Prussian, and Portuguese rules are all in varying stages of completeness. Also included are notes on the costs for making various profiles.