Cloning this repository:

git clone git://gitorious.org/~vlad-fazzza/android-n900/vlad-fazzzas-nitdroid-installer.git vlad-fazzzas-nitdroid-installer
cd vlad-fazzzas-nitdroid-installer

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

git remote add vlad-fazzzas-nitdroid-installer git://gitorious.org/~vlad-fazzza/android-n900/vlad-fazzzas-nitdroid-installer.git
git fetch vlad-fazzzas-nitdroid-installer
git checkout -b my-local-tracking-branch vlad-fazzzas-nitdroid-installer/master_or_other_branch