Accessories company Belkin has announced a new product, the TuneCast Auto Live FM transmitter. It allows you to broadcast an FM signal, but control that signal via an iPhone application.
The device uses GPS co-ordinates to determine your location, and then suggests the best FM frequencies based on that. It's the first to use an iPhone application to do so.
The ClearScan Live application is free to download from the App Store, but it isn't much use until you've got the Tunecast Auto Live hardware, too. That will be out in "autumn", and pricing is still to be confirmed.