Originally Posted by VistaBlueGT/CS
A quicker and easier option you may want to consider would be something like the GoGroove FlexSmart X3 Blue-tooth FM Transmitter. I have an '07 and just bought one ($50 shipped); my bro-in-law recommended it, and I'm pretty impressed so far.
Not as nice as a factory unit, obviously, but pretty cheap and easy!
I went that route before I got my aux jack and it was a pain getting a frequency that worked throughout my commute. If you're okay with its imperfections, then it is a fast and cheap fix. But if you're like me and get annoyed by micromanaging it, then it'll eventually end up in the garbage and you'll go to the better quality, more involved, option.