You can download the debian packages but for me they didn't work with mplayer so I did it from source. If you're interested this is how I got it working:
compile kernel with sound modular, alsa modular and your sound card modular.
download source code
install driver, install libraries, install utilities
in the alsa-driver folder run ./snddevices
run alsamixer set volume
There is better documentation in the alsawiki at http://alsa.opensrc.org/