A key feature of in-car GPS devices are the automatic turn by turn directions. You can get them on a phone, but depending on your platform, it might cost you somewhere in the order of $80 (for TomTom's iPhone app).
Which is why Google's announcement that it has made turn by turn directions (under the name Google Maps Navigation) available for Android phones so interesting. The way Google sees it, it has added the missing link for smartphone navigation - once you've read the reviews of a restaurant or hotel, decided where you want to go, then found it on the map, Android phones can now tell you how to get there.
The feature is only for Android phones for now. The iPhone version of Google Maps for Mobile can tell you how to get from A to B, but on Android it now provides speech instructions telling you where to go, 3D views of maps and automatic re-routing if you venture off course.
The "Route Info" function lets you see a choice of several routes, including the distance of each route, and an estimate of how long it will take to drive. In-car GPS devices like those from Navman offer similar features. You can also see the destination using Google's Street View, and search maps by voice.
On Android phones (1.6 or later), Google now includes its recommendation feature which lets you add ratings and view comments about nearby businesses like hotels and restaurants. Not only that, but Google also pulls in recommendations from Tripadvisor and Booking.com, two incredibly useful sites for planning and researching holiday travels.
There's also the ability to sync your map searches between your desktop PC and phone, plus integration with email and calendar entries.
One of the key advantages of Google's approach, as the company sees it, is that all this data is always up to date. The downside is that all the processing happens in the "cloud" on Google's servers. Lose your data connection and the phone won't be able to re-calculate your routes.
The screen size limitations of smartphones means that it's often ideal to have someone in the passenger seat to do your navigation. But if you're walking or have the time to stop and consult your phone, then Google Maps Navigation adds another feature to your toolkit.