Last Thursday the freenigma project was announced during a presentation at the LinuxTag. Freenigma is build completely on Free Software and will be available in September as a Live-CD as well as on separate Debian packages. We are currently doing internal testing, cleanups and preparing a release.
It is a successor of the old GEAM project which was a bit complicated to setup and configure. freenigma comes with a nice web interface, roles, backup and key generation and is fully integrated with an MTA (Postfix). It may be used as a plugin replacement for an existing MTA or integrated into an existing MTA structure to start using it.
As of now it supports OpenPGP. On demand we will add S/MIME encryption and signatures too. Appliances based on this software will be available soon to further simply the deployment of email encryption and signatures.