If you are not currently using git for your packages, you need to convert them to git before you can use GitHub.
During this process you will need to map svn usernames to github emails.
To do so please refer to the SVNUsrtoGitHubEmailMap.
Subversion (svn) to Git
Please use the github recommended migration tool here: https://help.github.com/articles/importing-from-subversion
Mercurial (hg) to Git
This blog post is currently the best option we have found: http://christoph.ruegg.name/blog/2011/7/30/cleaning-up-after-migrating-from-hg-to-git.html
Git to Git
Just push to the new repo (GitHub will give you the commands when you create the new empty repo)
If you have another suggestion please add it here.
To migrate the trac instance you will need access to the trac database. To get access to a snapshot of the repo please email firstname.lastname@example.org.
Trac Tickets to GitHub Issues
There is a useful script to help move tickets from trac to GitHub https://github.com/tfoote/github-migrate-trac-tickets
Trac Wiki into Github
If you have content in your trac wiki you can import it using these instructions