When Garmin curtailed its hardware partnership with Asustek late last year, you had to know the company would make a comeback to the mobile front in some shape, fashion or form. Starting today, the iPhone and 3G iPad both get the all-new StreetPilot app, which costs $39.99 and provides you with turn-by-turn navigation from the guys who make their living from the stuff. It undercuts TomTom's $49.99 offering for iOS, while offering real-time traffic data, vo
