nautilus-bzr is a plugin for Nautilus that integrates Bazaar, developed by Jeff Bailey and Jelmer Vernooij. It is built on top of the nautilus Python bindings.
The aim is to provide a simple graphical frontend to Bazaar that is easy to use for people new to version control systems.
This plugin is now part of bzr-gtk. To install it, read the instructions on the bzr-gtk page.