GHQ, maker of those fabulous microscale armor and ships has a tutorial on making ocean hex tiles. The techniques also could be applied to other terain forms, such as those large styrofoam squares so many seem to use.
They Don’t Like it Up ‘Em Colonial Campaign Rules
They Don’t Like it Up ‘Em is a set of free wargames rules for colonial campaigns.
.45 Adventures Free Downloads
Rattrap Productions has a set of free downloadable demo rules for its .45 Adventure miniatures rules. There also are a number of free scenarios.
WWII Air War Campaigns
JD Burgess’ site has a list of major WWII air war campaigns. For each, he has lists of the planes that participated, with links to photos and information.
Building Desert and Martian Terrain
This video describes how to build some terrific looking desert and Martian terrain.