You can download the distribution packages of the latest official releases here:
Snapshot Builds can be found here. Those builds are only refreshed if there have been any changes to the Git repository.
You can use the package repositories for installation.
The vanilla sources for the official releases can be downloaded here.
The current git repository can be cloned read only via HTTP by executing the following command:
git clone http://git.mathias-kettner.de/omd.git/
The git repository can also be viewed by using gitweb.