Car speakers to stereo mini ack

I'm wanting to get all the speakers in my car to get input from a normal 3.5mm audio jack. What would be the best way of going about doing this?
Thanks

What kind of deck are you using?

Audio will all be coming from this:
http://www.digitaletc.com/item.php?ref=fr&productid=5211
Mounted in the dash.

depending on the mp3 player you use, you could use the usb cable interface.

No, I'm not connecting an mp3 player. I need a way to get the audio from the device I linked to above to come from the car speakers.

What kind of headunit do you have? If you aren't using a headunit you'll need an external amplifier of some sort. If you go the HU route, just run an 3.5mm cable from the headphone port on the computer to the aux in on your HU assuming you have one.

If you go without a headunit, rig up a 4 channel amp and run a 3.5mm to RCA cable into the the front signal input on the amp.