A GPS program called the Navizon Virtual GPS has been developed for the iPhone and is now available for download through Installer.app. Users of the application report that the program works fine (it's known to crash one device though) and accurate within a few hundred yards.

The application isn't strictly to be called a GPS program though, as it does not get its data from satellites but through Wi-Fi. The system utilizes a database that collects data from users who do have GPS devices (the satellite kind). They contribute the data to Cell towers and Wi-Fi Access Points. The iPhone picks up the info and triangulates its position using the data.

This new kind of mapping by Navizon is called Peer to Peer Positioning, as it is dependent on the data collected by others to work. And because it's dependent on data from other people, the program isn't free. You're free to try it for the first 15 days but after that it'll cost US$ 24.99.