Apple iPhone 3G and 3GS users can get their hands on a free sat nav app, thanks to Skobbler.

Skobbler, which offers visual and audio navigation, utilises OpenStreetMap (OSM), a Wikipedia of free maps, that currently has some 250,000 users creating and updating existing maps.

The company also encourages users to make corrections and update the maps, to make "outdated and poorly detailed maps a thing of the past".

"Skobbler is the first truly usable voice-guided sat nav solution to use free map data that can be edited," says Marcus Thielking, co-founder of skobbler.

"All those who have edited the map have experienced a real sense of achievement. Everybody can make sure that their respective neighbourhood has the best map coverage. Editing the OpenStreetMap is already an ongoing project for many, which in turn ensures that the accuracy and usefulness of the data will continue to rapidly increase."

The only snag is that the free version of Skobbler is supported by adverts.

However, for £1.19, iPhone owners can get their hands on an ad-free version of the navigation app, which also comes with speed camera alerts.

See also: Nokia owners can use own voice for navigation