I tried KnoppMyth (a bundled version of MythTv and Knoppix designed specifically for a PVR) once but had some issues with my tuner card. About a month ago, I installed Ubuntu Dapper Drake and installed MythTv through apt-get.
After a bit of tweaking, it worked perfect.
It isn't terribly difficult, but it can take some time. I suggest following an install guide for a specific flavor of linux.
EP, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS