The "Wednesday Gamers" have been playing an Age of Sail game in my absence. (I have had work and family events that prevented me from playing.) And so, I have been an armchair admiral for the last few weeks. I am currently reading N. A. M. Rodger's The command of the ocean : a naval history of Britain, 1649-1815 to get better acquainted with the period. I also read the article, review, and reply to Douglas Allen's fascinating analysis of the economic incentives that made the Royal Navy and so Britain a great power: The British Navy Rules: Monitoring and Incompatible Incentives in the Age of Fighting Sail. (Also for free.)
While looking online for Age of Sail game rules I came across Jeffrey Knudsen's http://www.warartisan.com/ and his wonderful paper-craft models. I have not yet built any (armchair restrictions), but I have to say that the instructions are top notch. Even if you have no intention of making a 1:900 scale square-rigger do read the instructions for the 64-gun ship of the line and rigging tutorial. They are models of instructional clarity.
While I did not find the rules the Wednesday Gamers are using I did find the board game Fighting Sail which I want to try. The game was published by Simulations Publications, Inc. (SPI) many years ago and long out of print, but thanks to pack-rats and their pimp I was able to buy an unpunched copy.