Just completed the PADI Nitrox course, and downloaded the paid version of IScuba. This will make life a lot easier!!! Also, dont overlook this tool even if you just dive air. The multiple dive planner works for air, enhanced air, and any combination and since it displays all of the dives, you can tweak one and see how it will effect the others. A really terrific tool.
wingwiper about iScuba Plan