kicad files ( sources and others files) can be found at:
https://launchpad.net/kicad

Kicad repository at Launchpad uses bazaar.

If you want to get sources see:
https://launchpad.net/kicad/stable for stable sources
or
https://launchpad.net/kicad/testing for last features versions

documentation and translations can be found in a separate branch, at
https://code.launchpad.net/~kicad-developers/kicad/doc

libs (libraries for schematic and board editor can be found here:
https://code.launchpad.net/~kicad-lib-committers/kicad/library

You must have bazaar installed on your computer
create a directory kicad_dev, cd kicad_dev and run the following bzr command:
bzr branch lp:kicad/stable stable
to install sources in kicad_dev/stable.

or for users who want the latest development version (with bugs...)
bzr branch lp:kicad testing
to install sources in kicad_dev/testing.

and
bzr branch lp:~kicad-developers/kicad/doc doc
to install doc and translation in kicad_dev/doc

and
bzr branch lp:~kicad-lib-committers/kicad/library library
to install components and footprint libraries in kicad_dev/library