NDrive Navigation System, S.A has NDrive USA (iTunes Link) in the iTunes App Store for $2.99 (normally $29.99) for a limited time. Deal is limited to the first 1 million downloads

NDrive turns your iPhone 3G/3GS into A FULLY FUNCTIONING GPS NAVIGATION DEVICE, ready to use in the car, while walking in the city or during outdoor adventures. All map data is stored on your iPhone so you can NAVIGATE WITHOUT A NEED TO PAY FOR ADDITIONAL DATA DOWNLOADS OR 3G COVERAGE.