There are a number of repositories associated with QMachine, and they are all being transferred to the QMachine organization on GitHub.
The main project repository is the best place to start with development. It is structured as a superproject, which means that cloning it requires cloning its submodules, too:
$ git clone --recursive https://github.com/qmachine/qmachine.git
There are also "mirrors" available at Bitbucket, CodePlex, GitLab_, and SourceForge. The repositories at Gitorious and Google Code will no longer be updated because those hosting services are being shut down.
The source code for a very incomplete Python package is available at https://github.com/qmachine/qmachine-python.
The source code for an experimental R package is available at https://github.com/qmachine/qm-r.