A couple of questions for you:
1) What distribution are you using? (You profile says Ubuntu 11.04, but I don't like to assume.)
2) Is the machine going to be a backend only (i.e. just the recording server), a separate backend and frontend (i.e. client viewer only), or both a backend and a frontend?
3) Can you confirm that the Radeon 9200 has a TV tuner (maybe the output of lspci)? I googled but just came up with a video card only version, which will only allow output, not input for recording.
Beyond that, I googled and found
this for Ubuntu (note there is a "Part 2"
link at the bottom).
Also, the
Mythtv Wiki is pretty helpful. Anyway, I installed a frontend and backend on the same machine (so no network setup stuff) and the process went something like a) install mythtv and its dependencies, b) run /usr/bin/mythtv-setup, c) get a subscription to
Schedules Direct (which provides TV Guide information).
Another option would be to download and install a Mythtv specific distro like Mythdora, Mythbuntu, or LinHES (Formerly known as KnoppMyth).