Cloning this repository:

git clone git://gitorious.org/buildtorrent/buildtorrent.git buildtorrent
cd buildtorrent

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

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