Click here for the latest release.
To get the most up to date code, use subversion to check out a copy of deme repository. The command is
svn checkout http://groupspace.org/svn/deme/trunk deme-trunk
Deme is fully open-source, free software. It is currently licensed under the Affero General Public License (very similar to the GNU GPL, updated for the web). Deme is Copyright © 2003-2005 Stanford University.