http://www.creative.com/products/product.asp?category=13&subcategory=55&product=14309
This is the howto and if you plan to go multi channel I would recommend the cable too
I have been playing with this for a while now and with the upconverting capability of the X-fi card it really is a waste of time to rely on the digital decoder in your receiver.
I simply connect in analogue multi channel to the reciever ( using the creative HTPC breakout cable). The benefits...