Ah, answered my own question: http://www.mythtv.org/wiki/index.php/Backup_your_database

I think I just need to dump the database and then restore it under the new setup. Other than that I'd need to just point MythTV to the location of the .nuv files on the file system. Hope this works. I don't want to lose hours of Futurama...

I was wondering if anybody knows whether it is possible to back up old shows and then import them into Linux MCE (I currently run MythTV on Gentoo). Any tips would be greatly appreciated.

Damn, I really would like to get my hands on this ISO. Too bad the torrent right now is not working for me. Once I get it I could mirror it via http for a while though.