Begin your studies with the The American Colonist's LibraryNice set of links, thanks. Much of it I've seen already. I found the link to the Danbury letter interesting because it's to the Wallbuilders site, and it's no longer valid. Barton rearranged his site, much like he had to re-arrange his arguments when he learned that a number of the quotes he had been using were inaccurate.
There's no doubt that most of the Founders and Framers were Christians, and some that may not have been approved of Christianity. The question is whether or not they intended for Christianity to be an integral part of the government. There's quite a few links there that suggest the answer is no. Too many to claim, as some do, that Christianity isn't in the Constitution because it was presumed or implied.
-Eric