On February 11th 2013, we will be shutting down the MusicBrainz hosted Git repository, in favour of using GitHub for hosting. While we will continue to take backups, these will be internal and thus git.musicbrainz.org will cease to operate as it currently does.
There are a few reasons for this move, but the predominent reason is so MusicBrainz can host less. We currently host a lot of our own software and this is straining the already-limited resources we have. If someone else can do something just as well or better than we can – then let them! Using GitHub also means we get a slightly better repository browser, which can make communicating and discussing code easier. However, we are not moving to pull requests, though we may in the future.
We already mirror git.musicbrainz.org onto GitHub, so if you are only interested in read access, we recommend changing your local clone now, to save confusion in the future. To do this:
cdto yourmusicbrainz-serverclone.- Run
git remote set-url origin git://github.com/metabrainz/musicbrainz-server.git
That’s it! You should now be able to git pull just as you did before.
GitHub has a few other possible protocols for cloning, so if HTTP or HTTPS is better for you, then check out the GitHub repository for all the possible links.
If you’re a developer currently developing against our repositories, then you should either fork the repository on GitHub, or contact us to talk about getting your keys added.
Sorry for the disruption!
MetaBrainz Blog 
I think this is a good move towards more contribution. However, I think the change to GitHub pull requests is inevitable, and will follow in the near future. It might not have all features that codereview has, but it is just so convenient for people (which all use github).
Good Move!