HTML5 and the future are coming to a mobile browser near you and faster than we may have expected. Over on Maximiliano Firtman's blog he talks in detail about some of the new features available in Safari in iOS 4.2.
*Accelerometer
*Gyroscope support through the DeviceOrientation API
Obviously since PhoneGap leverages webkit on the device your PhoneGap based apps will get acces to these great new features too. Quit doubting web technologies and start thinking cross platform!