The Wargames Table has a nice article on modeling trees for The Great War. The trees also look to me as though they would be nice for a deadlands type of fantasy setup.
Final Round WWII Skirmish Game
Final Round is a set of free wargames rules for WWII skirmishes.
Gaming Card Creator
Here’s an online gaming card creator that lets you produce basic cards — sans illustrations — for a variety of gaming applications.
Rules For 16th to 19th Century Naval Wargames
Erik Springelkamp offers a set of free wargames rules for 16th to 19th Century Naval Wargames.
Crimean War Rules
Natholeon’s Empires has a set of free wargames rules for the Crimean War.