this guide was written with the Steel Panthers: World at War game in mind, but the principles should still apply, especially since you seem interested in WW2 (A&A minis)...

http://spwaw.com/lholttg/spwawtg1.htm

I found this essay on naval combat to be insightful.

ftp://ftp.grognard.com/download/games/board/tactics.txt

For World War II tactics (and TO&E and a lot of other great stuff), head to bayonetstrength, http://www.bayonetstrength.150m.com/Tactics/infantry_tactics....

It may be a little too "real life" and specialised, but I found the US Marine Corps manual "FMFM-1: Warfighting" to be a bit helpful in tabletop wargaming. And it's free! (PDF format)

http://www.marines.cc/content/view/82/56/

Also, "The Art of Maneuver Warfare" really improved my wargaming! The second half of the book is an examination of the US military, but the first half is a study of the terms, principles and theory of maneuver warfare that taught me quite a lot. It certainly made me a better wargamer. I can't recommend it enough.

http://www.amazon.com/Art-Maneuver-Warfare-Theory-Airland/dp...

Also, it sounds trite but "The Art of War" by Sun Tzu is a very good philosophical text on war. He doesn't give direct advice like "Artillery goes in the back." or "Don't place tanks on top of a hill." but more general advice like "Water flows around the rock." or "Security against defeat implies defensive tactics; ability to defeat the enemy means taking the offensive." Understanding him takes some thought and reflection, but it's very well worth your while to make the effort. And it's free!

http://classics.mit.edu/Tzu/artwar.html