take an optical\digital out from your sound card and plug it into the recivier's inputs....thats the easiest way, you can also convert a jack to 2 mono jacks and plug it in via composites, etc etc. millions of ways we need more info!! soundcard? recivier?
im starting to question rather or not people actually look for answers before they make these threads. there so incomplete and so lazy, i bet you didnt even bother to google an anything beforehand. nor did you provide enough information to even begin to answer the question [/Rant]