I've setup an HTPC with xbmc, and I'd like to output the audio from the system to both my digital and analog outputs on my mother board. How do I do it? Can their be a script that duplicates the output of one to the other?

Here's what aplay -l said:

**** List of PLAYBACK Hardware Devices ****
card 0: NVidia [HDA NVidia], device 0: VT1708S Analog [VT1708S Analog]
Subdevices: 2/2
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
card 0: NVidia [HDA NVidia], device 1: VT1708S Digital [VT1708S Digital]
Subdevices: 1/1
Subdevice #0: subdevice #0

It depends whether the sound device supports it.

Using pulse audio preferences, you can check "Add virtual output device for simultaneous output on all local sound cards" on the Simultaneous Output tab.

You may need to install paprefs and pavucontrol first.

Alternatively, you could try setting up an alsa plugin copy but that is more complicated.