http://www.completegettysburgguide.com/home.htm
This book is by two people who have contributed significantly to our knowledge of the battle. Check it out.
-Jim
Complete Gettysburg Guide
Complete Gettysburg Guide
"My God, if we've not got a cool brain and a big one too, to manage this affair, the nation is ruined forever." Unknown private, 14th Vermont, 2 July 1863