Waze is a free turn by turn sat nav application that relies on users to generate its data. As you drive you automatically tell it about the roads, average speeds and your preferred routes. This means routing based on actual speeds people did making similar journeys in real time which should work better than TomTom. Also if you are driving along and another user up ahead gets stuck in traffic you will automatically be rerouted around the traffic seamlessly. Obviously this will really take off once everyone has it - at the moment they have around 2 million users worldwide. I have told my London Cabbie friend about it and he will spread the word with them.
What hardware do I need:
* Any Android based phone (running OS 1.5 / cupcake as minimum)
* iPhone (running OS 3.0 or higher)
* Symbian based - such as the Nokia E71x (running Symbian series 60)
* Windows Mobile (running OS 6.0, 6.1 or 6.5)
there is also a beta for blackberry that works on:
BlackBerry® Bold™ 9700
BlackBerry® Tour™ 9630
BlackBerry® Bold™ 9000
BlackBerry® Curve™ 8900
Obviously you need GPS and a data connection.
You can also edit maps to fix problems and alert other users in the area to hazards, police speed traps (in real time) and accidents - you can even post a photo for other user to see for themselves.