It looks like it's a highly interactive process - much more typing than with KnoppMyth. That's good and bad. Good because you understand it better and can fix things if they go wrong. Bad because if you've got hardware that's not exactly what they're using, you have to try to figure things out on your own.
It scares me a bit too much to try right now, and there's still the Gnome issue with Ubuntu, and upgrading MythTV seems to be problematic.... I note though that someone says (in the [link|http://www.abarbaccia.com/component/option,com_smf/Itemid,39/expv,0/topic,54.0|forum]) the same procedure works pretty well with Kubuntu.
Here's a pretty detailed step-by-step rundown on how to install MythTV on Ubuntu (including HDTV). It was last updated in January. What I really like about it is that it even tells you how to do the wiring. :-) But the wiring diagram is missing. :-(
[link|http://patrick.wagstrom.net/tutorials/mythTV64/mythTV64.xml|MythTV, Ubuntu, Athlon64, WinTVPVR, Comcast Digital Cable, and a pcHDTV HD-3000 in a pear tree!].
Cheers,
Scott.
(Who may try to install the latest KnoppMyth this weekend.)