Just finished Agincourt, and was really impressed with the image the author produced of the battle. I agree with Cornwell that the archers were more than likely on the flanks, with the Men-at-Arms in the center. Having archers intermixed with the infantry would have created a weak line and probably would've broken, although it's still hard to imagine having nothing but archers protecting your flanks in a battle.
Some of you have talked about reading his other Saxon books. I highly highly suggest you read Jack Whyte if you're interested in Roman Britian. The first and second books are the abolute best I've read, and they are called "The Skystone" and "The Singing Sword."