To clone the master development repository, install git, and run:

git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git v4l-dvb
cd v4l-dvb
git remote add linuxtv git://linuxtv.org/pinchartl/uvcvideo.git
git remote update
git checkout -b media-master linuxtv/master

If you want to clone a different repository, just replace the URL at the git remote add line above.

For more information about git, see an overview, the tutorial or the man pages.