Cloning this repository:

git clone git://gitorious.org/rhythmbox-youtube/rhythmbox-youtube.git rhythmbox-youtube
cd rhythmbox-youtube

Add this repository as a remote to an existing local repository:

git remote add rhythmbox-youtube git://gitorious.org/rhythmbox-youtube/rhythmbox-youtube.git
git fetch rhythmbox-youtube
git checkout -b my-local-tracking-branch rhythmbox-youtube/master_or_other_branch