Mount Everest 3D is a free universal iOS app that brings you up close to the highest mountain in the world using 3D data gathered from satellites to give you the ability to explore the mountain with a touch interface. You can zoom, rotate and follow the most popular routes up to the summit of Mount Everest. The app also shows weather in the area, details for hardy tourists and a 2D view.
The app also has the inevitable in-app purchase, which lets you download maps and info for use without an internet connection, but I think most people can get along without it. The on-board maps are US$5.99.