For a while, standalone GPS navigation systems ("sat nav" in Europe) were getting popular and affordable. Many people were buying them for $ 100 to $ 200. Now, smart phones like the iPhone are increasingly being used to provide directions without needing to buy a separate device. There are a lot of different navigation alternatives available on the iPhone at varying costs and levels of convenience.
If you already have an iPhone, it comes with a Google Maps application built in. It can easily provide walking, bus or driving directions between almost any two locations. It can usually show your current destination on the map using GPS, but the downside is that you will need to read the written directions and it will not automatically move on to the next step when you reach it. Though inferior to many standalone systems, many people use this in order to not need to purchase and use a separate GPS navigation unit.
An increasing number of turn by turn navigation apps are coming to the iPhone AppStore. AT&T provides one for about $ 10 a month. Others are available for $ 30 or $ 60. Most recently, Tom Tom who is traditionally a hardware maker launched a $ 100 iPhone application which provides turn by turn navigation in a way that is nearly identical to their separate hardware units While $ 100 is expensive for an application, it's cheaper than a standalone device and won 't add any physical bulk either! Though new, reviews are quite good so far from early users.