I am running my audio out to home theater system and the mobos im looking at all say optical out or coax out...what do I get in order to have access to that input...do I need to get a soundcard to use it?
A mobo with an optical and/or digital coax out has a built-in sound card so none is needed. Just plug one or the other to what your reciever has for an input.
One or both of the connectors (outputs) are directly on the back of the motherboard, right below where you plug in your mouse & keyboard. The same connector (input) will be found somewhere on the back of your reciever.