My car is old enough that it lacks a built-in jack for an iPhone or an iPod. Does this deter my husband, who is not only physically connected to his iPhone, but a big-time music lover with a creative, diverse collection of songs? Of course not!
For our last few road trips, he's plugged in a dongle like this that transmits music stored on his iPhone over a free FM channel through my car stereo's speakers. Fantastic. It actually works (at least in those places where the radio gets reception.)
Today, Amazon's got the GTMax FM Talk/Transmitter on sale for $14.99, which is 63% off the list price of $39.99. If you've got a road trip in your future, this might be a nice tool to have along for the ride.