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

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

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.