We here in the Library get asked sometimes about sites of online, full-text books. There isn't any one place to which we can refer people, since such sites are a combination of paid and free, and there are truly a moving target as their developers add, subtract and alter the contents. But, here are a some suggestions which might be of use.
http://onlinebooks.library.upenn.edu/ Is a page of links to full text works which appears to be fairly current and which appears to emphasize recent publication.
Project Gutenberg http://www.gutenberg.org/ has an almost opposite point of view, it seeks to have volunteers enter the text of works on which the copyright has expired, so here one finds, almost exclusively, old books. This project has been underway for a long time and the file is huge, claiming to have the full text of over 17,000 titles now, and growing. There is a catalog which one may search, but, personally I find it somewhat awkward to use as a subject resource, works just fine if you are after a book for which you know the author or title, though.
Employing a different tactic a University of Ohio sponsored site has sound recordings. http://wiredforbooks.org/ The emphasis is on shorter works, such as poems, children's books, and even book reviews, some of the longer works considered to be classics are included, though. But, remember, your computer has to have sound for this to be useful for you.
And, lastly, there is http://netlibrary.net/WorldHome.html which claims to have over 250,000 books available (I haven't counted them) They arrange the books into “collections” and one has to register to use them. Frankly I don't think I want to read PDF files of some of the longer works of the world's literature, but, my eyes aren't what they used to be. For a lengthier list of online resources visit the library's Ebooks page.
Adrien Taylor, Reference Librarian