will feature real-time, turn-by-turn walking or driving directions, as well as 3D views, speech recognition and automatic rerouting.
It will initially be available in the US on Motorola's Droid phone, the first device to use Google's Android 2.0 software. The Droid goes on sale in the US on November 6 at $199 (£121) through Verizon.
One major difference between Google Maps Navigation and the sat nav devices produced by companies such as TomTom and Garmin is that Google's system uses the smartphone's internet connection.
Through the connection, Google Maps Navigation automatically receives the most up-to-date maps and business listings from Google Maps, meaning users won't ever need to buy map upgrades, and it receives live traffic data, meaning users will know if there is a traffic jam ahead.
It also allows users to access Google's Street View so they can see a more realistic view of their next turn or their destination.
Users won't need the exact address they're looking for. They can enter the name of a business or landmark, for example, and Google will find the address for them.
The news helped push the share price of Dutch firm TomTom down 21% on the Amsterdam Stock Exchange yesterday, while Garmin shares fell 16% on the Nasdaq exchange.
TomTom makes a software navigation app for the iPhone that sells for $99.99 in the US -- however, like other Google Maps features, Google's navigation service will be free.