How can I mirror a project hosted on launchpad on github?

You could try some kind of git-bzr bridge like this git-bzr git-bzr script:

This script allows you to add bazaar repositories as git branches in your git repository.
After that, you can fetch the Bazaar repo, make some changes, and push it back into Bazaar.

The reverse is possible, meaning you can clone a bzr repo and push to your GitHub repo with bzr-git.

Beware: trunk bzr-fastimport is broken and may corrupt your 'marks' file..

https://code.launchpad.net/~xrg/bzr-fastimport/re-tailor

A detailed implementation here:http://git.hellug.gr/?p=xrg/openerp-rebzr;a=shortlog;h=refs/heads/fast-only

I have just written a detailed how-to for mirroring a Launchpad Bazaar repo to Github (note that it focuses on Mac users).

A minimal version of this how-to:

1. Install bazaar and a plugin to make it work with git

brew install bazaarbrew tap gdubicki/tapbrew install gdubicki/tap/bzr-git

2. Clone the Bazaar repository

# for example:bzr branch lp:update-motd

3. Create the Git repository

You’ll need is the URL to the repo, in my case:

git+ssh://git@github.com/gdubicki/update-motd-for-non-ubuntu.git

4. Push the clone to the remote

cd update-motd # or whatever is the name of the Bazaar branchPYTHONPATH="/usr/local/lib/python2.7/site-packages" bzr dpush -v git+ssh://git@github.com/gdubicki/update-motd-for-non-ubuntu.git,branch=master