From July 4 - August 4, the World E-Book fair is providing free access to 750,000 e-books for free. A number of items in this collection are available for free year round (books to which the copyright has expired, government publications, etc.), but some are from publishers making their collections available at no cost for this month only. If nothing else, the site provides a way to search through the content of thousands of e-books.
Additional e-books are available in several of Langsdale's online databases such as Netlibrary and Creedo Reference.