In one of my Google search of a search of a search for an on line book; I came across this site. It seems like its a group of people trying to index on-line books. Lots of good old books (pre-1600) that are hard to find on-line. I came to the site somewhere at the bottom and had to work my way up, but I think I found my way to the main index.
General Index listing
F History United States (Regional), and the Americas
Let me know if you fine any interesting.