Everyone, please don't flag me as "advertising," the guy asked for a recommendation! Alos, I'm not affiliated and don't gain in any way if he ends up purchasing one of these.
Adam: Myself and a few people I know use the Following Card to get SPIDF Out and Dolby sound from their PCs
http://ncix.com/products/index.php?sku=35596&vpn=AZTXFF7102550&manufacture=AuzenTechAuzenTech does have a few other models as well depending on the features you're after.
Side note, that website is a Canadian Company. If you're in the states you'll have to shop elsewhere.
Hope this helps.
Snazzed