Simviation Forums

A panel you can pull up that connects to itunes so you can play your music

Unfortunately I do not know of one that connects to iTunes, however I know of a gauge that allows you to select a few individual MP3s to play during flight.
http://www.simviation.com/fsgauges_7.htm

I just have like AOL Radio on, or iTunes would work too. Just leave it on in the background, and to change a song, ALT + Tab to it and go back since Flight Sim auto pauses. Might take up some RAM but it works. Or well, there is the iPod too 

Here is one for FSX: http://simviation.com/fsxutilities1.htm