All source code is available to download from the downloads directory. Each release is signed with my GPG key.
Petmail is currently released under the GPL. Once the code is stable enough, I may consider relaxing that to the X license.
Petmail is written in Python, using the Twisted networking framework. The GUI agent application uses Gtk+ as a widget library. To run petmail, you will need the following libraries and tools installed on your system.
If you run debian/unstable, just install the following packages:
python2.3, python2.3-dev,
python-twisted (you may need to get a newer version from twistedmatrix.com,
as the debian version may be out of date), gnupg,
python2.3-gtk2, python2.3-glade2
A .deb is available via apt-get, so you can just add the following lines to your /etc/apt/sources.list and get the latest versions of both Petmail and Twisted, as well as all necessary dependencies:
deb http://petmail.lothar.com/downloads/debian/sid/ ./ deb http://twisted.sourceforge.net/debian/ ./
Some libraries and programs are optional:
python-imaging') is
needed to run a ticket server, or to run the self-tests that cover this
functionality.python2.3-gnome2').