Building HTPC 1st time and Have audio question

Ok this is probably easily answered but i cant find anything that tells me exactly what I want to know.

I understand that HDMI will transfer Audio and Video over a single wire but my question is this
If I plug the HDMI cable into my Motherboard and the other HDMI plug into the LCD tv, will it just pull Audio fom the PC's sound card without a cable running from the sound card to the TV?

And also if your sound card, onboard or otherwise has a optical out, can this plug into t[#f0000e][/#f0000e]he TV for sound or is this intended to hook into a Receiver?

I don't believe all motherboards support audio over HDMI. You should check that on the makers site. If not then use the SPDIF digital audio out (coax or optical) to your surround sound receiver and/ or the analog stereo out to the TV. There is no disadvantage in performance.