After you check off a few boxes on the Creative Commons license form, you'll get a page with the license for your work. This consists of a short block of computer code you paste into your book, image, web page, or what-have-you. This code displays a graphic badge showing the license you've chosen, with a link back to the license and a block of hidden "machine readable" text. This is text that search-engines can use to figure out which files are shared, and under which terms (you can limit searches on Flickr, Google, or Yahoo to only show Creative Commons licensed results).Link
Additionally, the machine-readable version links to two other versions of the licenses – a "human readable" plain-language version that can be understood by anyone, and a "lawyer-readable" version of small print that says the same thing in legally binding terms.
Creative Commons licenses are international – over 80 countries have their own CC projects – and something licensed under CC in the USA can be combined with Israeli, Indian, Brazilian, Spanish, British, South African and German CC works without violating the terms of any of their licenses.