For those who listen to their iPod in the car with one of those FM transmitter doo-dads, sometimes it is difficult to know what bandwidth to tune your setting such that you won't get interference from one of those stupid radio stations that tend to occupy the radio bandwidth.
But here is a website that will find the vacant FM bands for where you live, or where you are travelling to.
For my home, it's:
87.9 FM
91.9 FM
96.5 FM
101.5 FM
102.7 FM
105.1 FM
106.9 FM