using git checkout create a local copy for every remote branch: $ git checkout branch1, $ git checkout branch2 etc. (you may use the attached git-checkouter.rb script for this)
$ git remote add new-origin [REPO-URL]
$ git push -u new-origin --all
$ git push -u new-origin --tags
$ git remote remove origin
$ git remote rename new-origin origin
Local Git (for everyone)
create user account on the new git host
add your public SSH key to the host (somewhere in Settings)
get added to the team by the admin
in .git/config update the remotes (probably just one "origin") to the new repository URL
Deployment (only once)
on all servers, remove the cached-copy in the shared directory
in the app code: in config/deploy.rb update the repository URL
on all web-servers connect once to the git host, to accept the authenticity of the host, e.g. $ ssh github.com