I found a website with a lot of detailed information about medieval and ancient armies (unit types, tactics, etc.). I don't know if it is well known to the community or not, since I am relatively new. I did find it helpful in many ways. Obviously I don't have the time to fact check every piece of info they have, but it is certainly a good guideline at the very least. http://www.fanaticus.org/DBA/armies/medievals.html
