This is one of those apps that, once you start using, you don’t know how you did without.

Based on the technology from the maker of GPS devices, TomTom USA is a pricier app -- $49.00. Additionally, you can pay $19.99 for TomTom’s real-time traffic re-routing service.

TomTom USA is a perfect example of a company embracing an aspect of the iPhone that could have killed it. In iPhone 3G, Apple included GPS technology, and TomTom quickly presented an app that turned it into another TomTom device.

It works well, the real-time traffic feature can save hours per week in heavy traffic and, even if you travel and find yourself in various cities in rental cars, is always in your pocket. Frankly, the TomTom’s capacity to take geo-tagged photos on your iPhone and then map turn-by-turn directions to the location where the picture was taken was groundbreaking.

TomTom USA is an app to love.