Watch and understand.. CC video
Read More .. From the CC Licensing Page
"The following describes each of the six main licenses offered when you choose to publish your work with a Creative Commons license. We have listed them starting with the most accommodating license type you can choose and ending with the most restrictive license type you can choose."
Creative Commons provides free tools that let authors, scientists, artists, and educators easily mark their creative work with the freedoms they want it to carry. You can use CC to change your copyright terms from "All Rights Reserved" to "Some Rights Reserved."
http://www.youtube.com/watch?v=1DKm96Ftfko