There are a few "open" licenses available for use if you do not really want to copyright your work. The opencontent license and the GNU General Public License (GPL) has both been around for a while (GPL since 1991).
Creative Commons is a groups of bloggers and lawyers who has set out to create a new set of licenses :"these licenses will help you tell others that your works are free for copying and other uses -- but only on certain conditions"
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The licenses will be available from 2002-12-16 and the site includes some artwork as the shown "share alike" symbol.