Originally Posted by SpectreBlofeld
Many if not most new car stereos have aux input on the rear of the head unit to allow expansion for cd changers, satellite radio, et cetera. It's fairly trivial in this case to run an adapter cable from the rear of the stereo through the fascia of the dash somewhere (through a hole behind an ashtray, or through a glove box). Then you could plug the phone directly into the adapter by way of the 3.5 mm headphone jack. Much better sound quality than FM transmission.
Worst case scenario, you can buy a new head unit with front-panel aux input or bluetooth.
Now that would be sweet!! And very cheap. I have an '07 Magnum. I'll need to check if it has the aux input in the back. Thanks for the tip.