The Open Library project seeks to build the ultimate catalogue of books broadly using the same principles as Wikipedia. Its goal is to become the authoritative cataogue online so that users can find information quickly (currently only Amazon seems to have this depth).
I wish them well and really hope that they can create the library of Alexandria rather than Babel. Perhaps fears of mailcious user input are founded but they seem to be far and in between rather than a regular occurence. Definitely a proejct to watch out for in the near future.