Many years ago I started development of a computer program which would automate OD&D War Machine Rules. As a program it has the advantage over a paper-and-pencil technique of keeping track of all the pieces and the map and protecting them from pets and toddlers. The particular scenario which I first encoded (and is the only one to date) was module X10 - Red Arrow, Black Shield. Here it is.
The current version runs on Windows and is still in development at this writing.
Red Arrow, Black Shield program for Windows
The original version is also available. Download the executable and BGI to the same directory. It is a DOS graphics program, so it must run in full-screen mode under Windows.