The History Channel has an online, flash game about African Exploration. You roll dice (virtually), and try to accumulate miles and supplies, and avoid hazards. Its fun, and I can see a way to turn this into a neat miniatures game … I’m sure my friend Bob from Ann Arbor could pull it off.
The Wargames Factory — makers of hard plastic historical figures — offers a free 22 page article on the Zulu Army of 1879. Not coincidentally, Zulus are the current product on their list.
Square Hearts is a set of free wargames rules for colonial wargames in the 19th and early 20th centuries. It’s played on a square grid.
Savage and Soldier magazine has a good introductory article on the US v Philippine Insurgents in the early part of the 20th Century. It’s always struck me as a period that would make for a good game.
Here’s a set of African Colonial wargames rules from the Godfather of American Wargaming, Jack Scruby.