I use a free set by Brian DeWitt published in Wargames Illustrated blah years ago. The article was The Pain of Giving Orders if you can find it. One day I will post it on my blog because it is simple and works!
A quick look in http://snv-ttm.blogspot.com/p/wargames-magazine-database.html produced the following:
The Pain of Giving Orders; Brian Dewitt; WargamesIllustrated 50; ACW; Order system in ACW games using action cards
Tiny Tin Men Blog: http://snv-ttm.blogspot.com/
Wargaming Mechanics Blog: http://wargaming-mechanics.blogspot.com/