Most folks today have some sort of a MP3 player that they use to enjoy some of their favorite tunes.  There are times when you just want to listen to some of the latest and greatest that you have via your FM receiver.  Akihabara News .com had some information on a a new FM transmitter from Green-House that is available in 5 different colors.  There was not much information other than a few pictures but it certainly looks like it will complement your 3rd generation Nano.