You could use git bundle
and email one single file
See "backing up project which uses git"
A git bundle is just one file which can be very easily created and again imported as it can be treated like another remote.
Once received, you can clone it or fetch from that file.
As mentioned in "Backup of github repo", you will probably want for the first email to make your bundle with all branches:
$ git bundle create /tmp/foo-all --all
As Andreas mentions in the comments, Scott Chacon recently (March 2010) wrote a "cute" article on this topic in the ProGit blog:
Git's Little Bundle of Joy