I've recently started mirroring my git repositories to Github as well. It has some nice eye candy and tracking tools.
One thing that made it easy to migrate was brian d foy's github-creator package, which is a command-line tool to create a new repository on Github. You just run it from a distribution directory and it figures out a name and so on.
It's not a module (yet), so installing with CPAN requires an explicit distribution name:
cpan> install BDFOY/github_creator-0.13.tar.gz
If you're thinking of putting your CPAN modules on github, definitely try it out.