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.
Robert Cordery offers “Simple Colonial Wargaming Rules.” He writes
SCWaRes � pronounced “squares” � began life as a simple set of �fast play� rules for use with teenagers who had never played a traditional figure wargame before. The design parameters were: To have a turn sequence that kept the players involved throughout each turn; To have simple morale systems that dealt with unit and formation morale; To reduce the measuring of movement and weapon ranges to zero; To have simple systems for resolving fire combat and close combat; To include an element of uncertainty into the outcome of each game To produce a game that could be played to a conclusion in about an hour.