DVI-I does not do sound. You will need a DVI<->DVI cable, MiniDP>DVI adapter, and a (3.5mm headphone) male<->male or male>male or female RCA audio cable.
Thanks! I got everything except the miniDP > DVI - what wil that be for? Looking at the back of my tv, it seems to be the same size dvi-I fitting.
I think he assumed you had a newer Mac with MiniDP...
For audio, you will not be able to plug in both analogue and optical audio if that's what you intend to do; you will need to get a simple Y-splitter for the analogue stereo or one of these to split the optical to your two receivers.
Are you saying that I can't have my optical out from my computer going to my tv and the analogue jack out going to my computer speakers?
No, you can have the optical out hooked up to a receiver and the analog out hooked up to to speakers.
BUT you can't have sound going to them both at the same time.
Although some things can be set to use either one. Like system sounds can be set to go to the speakers and everything elese (quicktime/itunes) to the optical out.
Some apps (VLC) even let you specify the output in their menus.