OCLC has released worldcat.org which contains over 1.3 billion items in over 18,000 libraries worldwide. Basically, it is the super catalog in terms of amount of cataloged items. It is built into search engines such as Yahoo and Google. (Interesting note, when you search for Rosen's Emergency Medicine, worldcat is the first link displayed on Yahoo, but is burried in Google search results.)

Librarians can put the WorldCat search box on your site so that when your users visit your home page they can try looking WorldCat if your library doesn't have something.

Librarians can also provide a link so that users can add WorldCat to their browser toolbar

For more information on check out, What is WorldCat and See other ways you can use WorldCat.

Libraries interested in adding your library to WorldCat go to, Put your library in WorldCat.