Google Book Search
I found my favorite at http://books.google.com/books?id=Hg0jKHsj6DMC&pg=PP1&ots=RXt_4zyzEB&dq=confederacy+of+dunces&sig=ZAdzeHYGXN7iBZoA-mJx-TyROq8 . Google has had this available for a little while and the reason I’m noting it here is that I read an article this morning which mentioned the fact that they are using OCR to scan all of the books. I think it won’t be long until thier entirely is available within a web search.