I recently added another bttv capture card (AITech Wave) to my system and couldn't find anything posted about how to configure two cards. I did a bit of searching and the answer was pretty simple.

Edit the 'options' line of your '/etc/mythtv/modules/bttv' to list the card and tuner values as a comma seperated list. Here's how my options line looks:

options bttv card=64,35 tuner=2,2

I then rebooted and both cards were configured correctly.

Also, the capture card in the highest pci slot (closest to the cpu) is capture card 0.

Hope someone finds this information useful.

my question would be how are you handling the sound.

Had to add a second sound card. See my post in hardware for the how-to on that one. It's a bit more complicated, but I think I laid out the procedure fairly clearly.