Anyone may choose a Creative Commons license by going to http://creativecommons.org/license/
Several services are available to integrate license selection into a website or application:
Requires minimal knowledge of HTML.
Documented at http://api.creativecommons.org/docs/readme_15.html#simple-chooser or merely go to http://api.creativecommons.org/rest/1.5/simple/chooser for the simplest invocation, which obtains a list of license URIs and names in the form of a select list (which can be easily parsed if you wanted a list of licenses for use elsewhere).
Documented at Web Integration Guide
Screenshot below, example described at Movable Type.
Allows any website or application to transparently integrate CC licensing.