If the maps are stored locally, then yes.
...
If you're in a remote part of the world without at least cell towers within your reach, the iPhone's GPS and therefore TomTom would be pretty useless.
Gloss claims the contrary! I kind of doubt that this is the case, that's why I asked about it here:
iPhone A-GPS --- works without mobile network?!
Let's play the Price is Right here...
TomTom App: 99¢ (can't be free because of In App Purchases)
In App purchases:
City Maps: $9.99
State/Region Maps: $14.99
Country Maps: $29.99
Dock: $99
I'm not sure if everyone is intelligent enough to get the mechanisms of the app store yet. Obviously, rather cheap apps get way higher numbers in sale... but TomTom and Navigon always seemed to be rather greedy. Hm... TomTom has very high debth and is about to go bankrupt, maybe that'll make them change their policies