One of my favorite web 2.0 tools is worldcat.org. WorldCat.org lets you search the collections of libraries in your community and thousands more around the world. I am proud to say that I contributed to this collaborative effort as a cataloger by creating original bibliographic records and adding these to the WorldCat database.
You can search for popular books, music CDs and videos—all of the physical items you're used to checking out from a library. You can also discover digital content, such as downloadable audiobooks, online article citations with links to their full text, as well as primary research materials, such as documents and photos of local or historic significance.
Once you search WorldCat.org and locate the item you want, you will be taken directly to the OPAC of the library nearest you to see if the item is available.
What is really great, is the ability to add table of contents, reviews, ratings, summaries and notes to the record of your favorite book, video, CD, or audiobook.
Have fun searching! I added a link (on the navigation bar on the right). Let me know what you think.