In this day and age, many Rec. divers use expensive dive computers. While extremely useful during a dive, the dive planning function on a dive computer is often a PITA to use, so many divers--even with computers--skimp. iScuba Plan is an excellent tool for planning your dives. I found it super-easy to use for air or nitrox dive planning. If it makes it easier to plan my dives, Im more likely to plan my dives, and that makes it a five star application in my book.
Reg Braithwaite about iScuba Plan