The following is everything I could find on good old Man-O-War. There are some groups out there which offer rules to their members (think Yahoo groups).
Here are some links and e-bay auctions which are available.
Its a game which died a long time ago, but it has alot of followers (like me).
Man O' War Man O' War | BoardGameGeek WARHAMMER MAN O WAR BOXED GAME GAMES WORKSHOP - eBay (item 380007034916 end time Mar-22-08 11:36:10 PDT) GAMES WORKSHOP WARHAMMER MAN O WAR COMPLETE UNPUNCHED - eBay (item 230231802957 end time Mar-19-08 17:33:53 PDT)
Hope this helps.