Easy Practice is an invaluable tool for the parent coach. With detailed step-by-step instructions, video examples and complete practice plans by age division, this is one of the simplest and best practice planning apps I've seen. It helped me get up-to-speed within my first few years of coaching. I wouldn't use it for every practice, but it provided for a great foundation that I began to build on.
The Soccer Dad app is a great tool for those coaches that like to pre-plan each game and track player times in each position. You can also share your plans with your assistant coach via a dropbox integration. When working to ensure fair play time and to pre-plan your subs, Soccer Dad is awesome. You can start the timer and track scores during the game. You can also have a parent enter player stats.