I'm running Ubuntu 8.10, Fglrx 8.53 (the one installed by the Ubuntu restricted driver manager) and TVtime 1.02 (from repository). Audio output is via the Bose System 5 (PCM via USB). Other audio (and everything else for that matter) works great.
Works on Winders XP with the Hauppauge software (Windows 7 beta, too but we won't get into that) so I'm pretty sure the hardware is working OK. Or, as well as it does.
Get good picture via the composite input, but no audio. The TVtime on screen volume control is at "0" and can't be advanced. There is good audio going into the Hauppauge from the cable box, and I can route the audio out of the cable box to an outboard amplifier/speaker or headphones and that works, but is not the desired configuration.
The PCM audio subsystem has no "mixer" where you can control various inputs. All you get is one volume control. That works and is turned up and not muted.
I tried to get this working with mythtv but my head exploded. I'll get back to that, but I have to heal (and replenish the bar) first.
TVtime actually does all I need right now, so if I can get that working I'll be happy again, but overall I gotta admit that my "I hate Linux" file was pretty small until I began this.