The free update will add lane guidance, which helps you figure out where you should be going on complicated junctions, and text-to-speech, so it can read out street names and points of interest as part of the spoken directions.
A new help menu will offer shortcuts to dial emergency services, and iPod controls mean you won't have to exit the app to change tunes.
TomTom said it has submitted the update to the App Store and as soon as Apple approves it, it will be yours for the downloading.
We thought TomTom was the best of the iPhone sat-navs we tested in our review. But since Co-Pilot also released a free update to its app, which introduced a proper Qwerty keyboard, we think the two are neck-and-neck.
With Google entering the sat-nav fray with mind-blowing, freein the US, it's no wonder TomTom is pulling its socks up. But here in the UK, TomTom, Co-Pilot and other traditional sat-navs still have the edge. They store their maps on the phone's memory, rather than downloading them as needed like Google does -- so they won't cost you an arm and a leg in data charges when you're abroad.
In other TomTom news, stay tuned for our review of the TomTom in-car mount, which pimps your iPhone with another GPS receiver and a suction cup.