Placement of App Inventor in high school CS curriculum
The AP course that @AlfredThompson referred to is the Mobile CSP course. It's a
complete College Board-endorsed course for the new AP CS Principles course and is entirely based on App Inventor.  It comes with a complete set of lessons for students (Creative Commons-licensed) as well as lesson plans and professional development (PD) resources for teachers.  The MobileCSP project has been providing PD for high school teachers throughout the U.S. since 2013 and has now trained around 500 teachers. For more information about the project, see this site.