Geology ID ($6.99 on iTunes) may be the best iPhone, iPod and iPad app about Idaho rather than the stuff that people say about Idaho or what people do in Idaho. This is really about Idaho: its mountains, valleys, aquifers, rivers, mineral resources, fault lines and about two dozen more so-called layers. Want to look at the state's fire risks? Done. Railroad tracks? Sure. Earthquakes? No problem. Geology ID is certainly a tool for geography and geology professionals, but it's also a geek's dream. Unlike Google Maps, Geology ID is completely self-contained, which means that it's always available, even without cellular or wireless coverage--it's great when you're hiking in the middle of nowhere. But it can also take advantage of the iPhone's built-in GPS receiver. With the swipe of your fingertip, you can zoom to your exact location. Working on a project for work or school? Geology ID can also generate high-resolution maps that download to your PC.