Drupal
The Drupal CMS has two modules that allow for easily licensing content nodes:
creativecommons-lite
"This has been built to make easier for user to choose creative commons licence while adding content as existing creative commons module is too complex with 2-3 steps procedure. This module does not uses any api for getting license because some license like developing nations is not supported by api."
See http://drupal.org/project/creativecommons_lite License needs to be selected per node.
creativecommons
The creativecommons module is only available for Drupal 4.7, It has not been updated for a long time. This CC Drupal module uses the CC web services API.