Binary packages for Fedora and Ubuntu will be added shortly.
eGFRD is implemented in C++ and Python. You can browse the code using a web interface to the Git repository.
To check out the development version of the code, make sure you have Git installed and do:
$ git clone git://github.com/gfrd/egfrd.git
The current implementation of GFRD is called eGFRD (the e is for enhanced).
eGFRD is currently a mirror of the E-Cell project. Changes are shared between both repositories, although E-Cell is usually slightly ahead.