MIT App Inventor is a highly visual mobile app development platform, which can be used by programmers and non-programmers alike. It is a great teaching aid for introducing computer programming.
The MakeUseOf Guide provides all the information that you need to get started and makes an excellent readymade student handbook. The aim behind the guide being "to show anyone the basics of using App Inventor in the hopes that more people will create instead of just consuming".
You can also download many more useful MakeUseOf pdf guides.