The latest official stable release can always be found here.
pyfa (python fitting assistant) - A cross-platform ship fitting tool, written in Python utilizing wxWidgets as it’s GUI toolkit. pyfa works on all platforms that Python and wxPython support, including Windows, OS X, and Linux. There is also someone who has created a FreeBSD port of it.
Simply download the package for the platform you want to use from the release page. Linux users: your package is basically a Tarbell of the source files; be sure to install the dependencies required. There are also some third-party packages for pyfa floating about for Debian and Arch that are maintained by third parties, check the README.
A complete listing of issues and their progress can always be found here. For bug reporting guidelines, take a look at the Wiki on GitHub.
All contributions are welcomed and done through pull requests on GitHub.