If you are looking for camera apps that brings something new, simple and cool then this is a good choice. It is called Dblcam and in essence it takes a photo with the rear camera and then takes one rapidly with the front facing camera. It captures the subject, but also captures whoever takes the picture.
Once you take the first picture with the rear camera, the app takes the second with the front-facing camera. Then the app combines the pictures in one and then you will have the option to share to Facebook, Twitter, Instagram or email.
The app is free and available in the App Store [iTunes Link].