Cloning this repository:

git clone git://gitorious.org/replicant/android_hardware_broadcom.git android_hardware_broadcom
cd android_hardware_broadcom

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

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