Creative Commons released an Add-in for OpenOffice.org which allows users to select and embed a Creative Commons license in documents. Based on work completed as part of the Google Summer of Code by Cassio Melo, the add-in supports Writer (word processing documents), Calc (spreadsheets) and Impress (presentations).
The Add-in is available without charge, and is licensed under the GNU General Public License. Download information and links to source code.