This app was mentioned in 2 comments, with an average of 1.50 upvotes
You can download the app straight away from the google play store. It doesn't do much without the book (it does allow you to print an image of Fluttershy for testing, which, yes, results in the ability to have a large virtual Fluttershy flying around, only visible through the phone's camera). Poking around in the settings, it looks like (if you have the book) you can also create a custom pony (I'm not sure exactly how customisable it is) which is then tied to a certain custom-pony picture. The pony can be moved away from the picture and (if winged) alternate between walking and flying at the touch of a button.
Ooooh, that's a useful guide. And much better than this option - your guide is way more customisable.