Who would have thought that iPhone developers would be so fast in coding apps. Apple iPhone developers like Ziconic have already designed a app making use of Digital Compass which is available only on new iPhone, iPhone 3G S.
AirCoaster 3D is an existing application that allows users to design and ride 3D roller coasters on their iPhones and iPod touches. They’ve since posted a video of a prototype version that takes advantage of the iPhone 3GS’s digital compass:
The app is still in testing phase and available in App Store(0.99 cents only)