Arduino Companion is an app for designed to help anyone getting into Arduino and electronics. The app contains the full Arduino Reference for offline use, as well as a handy resistor calculator. The Reference contains all of the basic Arduino reference, but it also covers all the included classes for controlling Ethernet, Servos, Serial Communication, LCD Displays, SD cards, Keyboard and Mouse (Leonardo) and more. Now also covers Arduino Due.
Feel free to contact me to suggest features you feel is missing or if you find any bugs. Contact me using the About-page inside the app or the email listed below so I can fix the issue.