Repository:Open Library

Open Library is currently (February 2009) in Beta testing. According to its "About Us" Page its goal is to have "One web page for every book ever published". A unique feature of the site is that it styles itself as "an open site" by which is meant that some of the information can be edited by the viewers. In their words "Now it's your turn! Everyone can participate in this project, whether you're a programmer who wants to build on top of this data, a librarian who wants to add records of digitized books to her local catalog, or a lover of books who wants to make sure his favorites are well represented."

More from their "About Us" page, with some rearrangement:

Open Library is a project of the non-profit Internet Archive, and is funded in part by a grant from the California State Library. This is an Open project - the software is open, the data is open, the documentation is open, and the site is open...To date, we have gathered about 30 million records (20 million are available through the site now), and more are on the way...you can search millions of book records, narrow results by facet, and search across the full text of 1 million scanned books.