GPS receivers have been a near-ubiquitous element of the modern smartphone since it was popularised by the Nokia N95 back in 2007, but for some strange reason turn-by-turn navigation hasn't followed the receivers into as many handsets.
This trend is changing, however, with Nokia making directions free to owners of certain phones running Nokia Maps 3.0 and with the launch of the first Garmin-Asus smartphone in Australia. These phones include turn-by turn directions in the cost of buying the phone, but there are also options with other smartphones to buy the maps separately via a connected applications store. iPhone users can choose between TomTom, CoPilot Live and Sygic maps, while Android users can purchase a CoPilot app.
Using your phone as your GPS system has a few key benefits. Firstly, the "always on" internet connectivity of your phone means these maps can download updated traffic information, and guides you to the points of interest nearby. Secondly, you get a GPS and hands-free speakerphone in one neat package, plus you have the extra security of dismounting your phone from the car dock and taking it away with you.