WorldCat.org lets you search the collections of libraries in your community and thousands more around the world. You don't need to install any special tools into your browser. Worldcat is already part of Google searches and more.
This is an example of a search at books.google.com
Click on Get this book in print and then click on 'Find in a library'. This link will open a Worldcat search with more information about the book and based on your local zip code, will show you availability in libraries near you.
Click on the linked name of the library you wish to search and worldcat will open a search of the library's catalog where you can find out about current availability, place a request, etc.
Worldcat.org has other fun and useful tools for members, such as tagging, bookmarking, linking and creating lists of items you own and recommend. Join worldcat.org for free today!