Audio w/ hdmi using GeForce 9800 GTX?

You will need to connect the SP-DIF pass through from you motherboard(assuming it has one )to your 9800 then it will pass the sound through HDMI, if your board does not have SP-DIF you can always get a pcix sound card that does have SP-DIF, or if its just for a HTpc without gaming, get a ATI hd4350 as this has sound passed through directly via supplied adapter through hdmi cable