geezer, there are several usb soundcard or usb -> coaxial audio converters that will do the trick. i'm not sure whether you need audio only or separate digital video and audio signals, but if you need just audio you can go with the converter that will output pcm to your dac. i believe xitel makes one that is 50usd that is very common. otherwise, any usb soundblaster external card will do the trick (though i've been told the audio quality for the soundblaster digital out may be comprimised...i have not confirmed). in either case, you have several solutions out there well under 100usd.