I'm not sure if there is an app out there for this or not. I have the car dock for my phone and use it to play mp3's through the headphone jack to my car stereo. I also use Google Nav at the same time and prefer to keep it on the Nav screen while I'm driving. Is there an app that will display the song and artist currently playing in the notification bar so that I can see it while I'm in the Nav screen? Is it something that I could do if the phone were rooted?