The most recent binary packages can be found at the GitHub projects releases.
Here is a mirror of that listing:
The most recent source package is in the master branch of the Git repository.
$ git clone --recursive git://github.com/PLRI/arden2bytecode.git
You can also download it from GitHub as .tar.gz or .zip.
To build, follow the instructions in the documentation wiki. It’s basically typing
ant at the command prompt.
To install Arden4Eclipse, drag and drop the following button onto a running Eclipse window:
Then follow the instructions on Getting started with Arden4Eclipse.