Below is a link of the first detailed look at the TomTom App for the iPhone. It's rather long so I'm posting the link. This comes via MacRumors Web Site. At $99 for the App it's nice to have a few good objective reviews before dropping the $.
Download and set-up
The TomTom app for the U.S. and Canada takes some time to download given its 1.21 GB size. The size of the app is attributed mostly to the map data it holds, carrying street-level data for the all of the U.S. and Canada, including points of interest (POIs). It can be installed on to iPhone 3GS and 3G models, though would not install on a first-generation iPhone.
Opening the app for the first time prompts a legal advisory to pop up, which must be acknowledged in order to proceed. After this, you are free to roam about and explore the app, with no settings prompts or "getting started" information shown. The voice is set to "Lori," a female American English voice by default. If you want to change the voice, you have a whopping 75 from which to choose in languages from Afrikaans to Vlaams. There are 11 voice selections that speak English available, though none of these are computerized voices capable of pronouncing street names. Changing the voice guidance language does not change the language of the app's English interface.