Inflight music player

[steelerspilot]

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

[SeanTK]

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

[The Snake 87]

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 

[RaptorF22]

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