I signed up for a free seven day trial for footnote.com today. They have tons of historical scanned documents, but they're a little hard to explore. The search is a basic Boolean search of either all documents on the site, or specific categories, such as Revolutionary War Service Records, Naturalization Records for certain states, Newspapers, Confederate Papers, etc.
So far, I've only found records for one ancestor, Wiley Powell. Wiley died during the civil war from illness. I was able to find records of his service, illness and death.
There are a few more that you can check out on flickr.