I was wondering if there are home server projects which have been released and are stable.
I have been keeping an eye on the Ubuntu Home Server edition but it's not out yet.
Ubuntu Home Server (UHS) will be an edition of the Ubuntu operating system which allows users to administer their home network. With Ubuntu Home Server you will be able to store all your music, songs and pictures in one central location, to access your files over the internet and to backup all the computers in your house.
The goal is to have a working release available with the upcoming Gutsy Gibbon release of Ubuntu (or perhaps Gutsy+1 at the latest).