This morning I have posted the updated Bungie.net/MythDev metaserver source code for downloading. This is being licensed under a BSD license - so go over everything and then have fun setting up your very own Myth metaserver for use with all three Myth clients.
It should also be noted that there is a forum over at MythDev for this stuff too. Oh, by the way, heres the link for the MetaServer. Enjoy!