I have developed a series of iPad App demonstrations for a large pharmaceutical company. These demos walk sales reps through how to use the various apps and present scenarios in which the apps would be beneficial. I came up with the idea of using screenshots or screen capture with the video of the hand overlaid on top and I think it worked out really well. Originally, they had recorded videos of someone walking through the app (see first image below) but the glare on the iPad screen makes the quality of the image inferior. The overlapping video approach makes the image much more crisp and also allows for more interactivity within the content.