I'm using Mythbuntu 9.04 and I nearly have it all setup. The problem is tha when I Watch TV i hear the sound twice, once from the line in and then again delayed from Mythtv actually saving the sound.

I use an old card that requires a jumper form the capture card to the soundcard. I followed this link http://www.mythtv.org/docs/mythtv-HOWTO-7.html to get sound working (originally there was no sound at all) but now the sound is played twice!

Here's what the link tells you to do to get sound working:
$ amixer set Master,0 100%,100% unmute
$ amixer set PCM,0 100%,100% unmute
$ amixer set Line,0 75%,75% mute captur
$ amixer set Capture,0 100%,100% captur
$ su
# alsactl store
# exit
If I just use a client to connect to my backend watching tv does not play the sound twice.