Toslink Optical Input

I don't really know anyone to ask so I figured 4chan would be as good a group as any for advice. I do HTPC on my computer. I play Playstation and I've noticed several of the games I have support 2.1 and even a few support 5.1 audio (Xenosaga for example) through the TOSLINK optical port. I'd like to both take advantage of that as well as record the full 5.1 audio stream if possible. Anyone know of any sound cards or anything that would do what I'm looking for, for under $100?

So you have an HTPC all hooked up, you play PS(2) games on an actual console, and you want to connect your console to your HTPC via digital audio cable in order to capture/record all channels and also have all channels play on your sound system through that connection.  Correct?