Public Domain means anyone can use it for whatever they want. You basically give away all rights to your work.
Creative Commons comes in four forms (and to save time I'll quote
http://creativecommo.../about/license/):
Attribution. You let others copy, distribute, display, and perform your copyrighted work — and derivative works based upon it — but only if they give credit the way you request.
Noncommercial. You let others copy, distribute, display, and perform your work — and derivative works based upon it — but for noncommercial purposes only.
No Derivative Works. You let others copy, distribute, display, and perform only verbatim copies of your work, not derivative works based upon it.
Share Alike. You allow others to distribute derivative works only under a license identical to the license that governs your work.
And there are other licences :)... I generally release anything I do under a public domain licence. I don't mind what people do with my work.
I hope this helps.