The soon-to-be-legalised practice of iPod playback via FM (see Griffin's iTrip) is to get a new participant, in the form of the Monster iCarplay Wireless 200.
Like other FM transmitters, the Monster iCarplay Wireless 200 allows you to play your digital music (from your iPod or iPod nano) wirelessly through virtually any FM station on your car radio, while simultaneously charging your iPod. The difference with the iCarplay is it'll automatically find the clearest FM frequency so you don't have to manually search for the best station.
Other features include three programmable “favourite station” presets, international modes that allow use in North America, Europe and Japan, three button control and low profile power adapter to minimize dashboard clutter.
All good stuff, but with an RRP of £80 the iCarplay is quite a lot more than most other FM transmitters available.
More info: Monster products