I found a very interesting paper titled
Camera-Based Motion Recognition for Mobile Interaction
Click here to access the paper on-line.
The cited work presents the state of art about computer vision based apps for mobile devices, some features that can be used for developing new apps and suggestions about resources that be added to the app, like GPS, RFID, accelerometer, etc.
In fact, computer vision based apps for mobile devices is a great field to research and develop interesting and useful solutions.