I have the same setup that Jordan (JE3146) and Ted (tedrogerscpa) outlined. I feed the audio directly into my receiever rather than to the TV, because my HDMI input doesnt have a separate input for audio.
If you're gonna feed audio directly to the TV you're gonna have to get this:
http://www.amazon.com/Apple-Mini-dvi.../dp/B00011KHTW
and send the signal through s-video or composite video so that you can send audio into the same input on the TV.