http://search.creativecommons.org will help you find photos, music, text, books, educational material, and more that is free to share or build upon utilizing Creative Commons enabled search services at Google and Flickr. You can also access this tool via
Creative Commons licenses provide a flexible range of protections and freedoms for authors, artists, and educators. ... Add CC Search to your browser. Learn how to switch to or from CC Search in your Firefox search bar.