Great Application overall. Sharp graffics. Address and lat/long function is simply amazing. In order for the compass to work on an iPhone 3G, you must be moving/travelling in a certain direction. It is not a static magnetic compass that will change bearings based on the way you hold your iPhone. The app will eventually provide a bearing, but the bearing is false unless you are moving in a line and a plot can be formed. Other than that slight problem, it is a really useful tool.