audiovox inline FM modulator
this thing is MONEY>
it works excellently. especially if you think installing amps and 9 miles of wires is gay when you have a perfectly good working HU with no auxillary input.
you just have to wire up a 12V source and don't forget to use the noise isolator that it comes with.
well worth the 49 bucks. this is the best and easiest way to install pc audio from your sound card to your car audio.
(you run a headphone line from souncard into a y adapter that splits it to the RCA cords)
circuit city actually has them in stock at the store for pick up, but it's hard to find, you have to ask them for one and they took a long time to find it in the storage.
the GLI that comes with the modulator is CRAP. it stopped filtering noise about 2 weeks into the installation. i simply bought a tsunami GLI for 15 bucks at Circuit city and it works fine now.
still worth the effort and money though.