TomTom U.S.A. for iPhone is half off until December 28th. It works fine although it did get lost once in the city despite being paired with the
TomTom car kit, which is supposed to enhance the iPhone 3G S' GPS reception. It also doesn't pronounce "San Francisco" correctly. Other nits include basic iPod controls that don't allow playlist selection, and requiring too many taps to access the controls in the first place. The TomTom app also requires extra taps to toggle day/night mode rather than taking advantage of the iPhone's ambient light sensor.