RLG has a search engine called redlightgreen (www.redlightgreen.com) which claims to have access to 120 million books.

RedLightGreen helps you locate the most important books and other research materials in your area of interest, and find out whether what you need is available at your favorite library.

You can log in with your e-mail address (password is optional), conduct a search, look for holdings at a library and also have your citation instantly formatted into one of the popular formats (APA, MLA, etc.) and it’s all free and available directly on the internet.

More information about this is available at: http://searchenginewatch.com/searchday/article.php/3560121