If you're DJing up your own tunes with one of those old iPod FM transmitters that doesn't auto-seek the best frequency, you're probably always fiddling with it to try to get the optimum sound while driving. Say goodbye to potential vehicular manslaughter charges by using this FM radio locator before you even leave the house.
Just plug in your zip code—and the zip code you're going to be driving to—and you can see what the radio frequencies and their distances/signals are for FM and AM stations around you. This lets you quickly eyeball a big enough gap for you to slide your transmitter into. Educational and useful.