TomTom turn-by-turn navigation software is now available for the iPhone 3 and 3GS. You can purchase map sets for USA and Canada, New Zealand, Australia and western Europe. The price for USA and Canada is $100 via the iTunes app store.
Engadget has links to reviews, and advice that it may be best to wait for the TomTom car kit. For $200, the kit provides a holder for the iPhone that mounts with a suction cup to the dash or windshield, a cable to link to the 12V power in the car, and the map software for the iPhone. The holder reportedly adds its own GPS chip that is more accurate than the one included in the iPhone.
http://www.engadget.com/2009/08/17/tomtom-navigation-for-iphone-3g-and-3gs-arrives/
Engadget has links to reviews, and advice that it may be best to wait for the TomTom car kit. For $200, the kit provides a holder for the iPhone that mounts with a suction cup to the dash or windshield, a cable to link to the 12V power in the car, and the map software for the iPhone. The holder reportedly adds its own GPS chip that is more accurate than the one included in the iPhone.
http://www.engadget.com/2009/08/17/tomtom-navigation-for-iphone-3g-and-3gs-arrives/