Just collating two existing resources. As with the first poster I like to store tutorial code, etc. in a private repo so that it doesn't clutter up my GitHub presence when I put something out there.
Import GitHub repo into Bitbucket
http://somatose.com/2011/10/from-github-to-bitbucket-in-60-seconds.html
Delete GitHub repo
https://help.github.com/articles/deleting-a-repository