[iPhone God App] It was found using the Stud Find actually

iPhone Metal Detector

⎈ For this app to work, the nails in your wall should be magnetic and your device (iPad, iPhone or iPod) should have a built-in magnetometer.

NOTE: The presence of Compass App in your device confirms a built-in magnetometer.

Use your iPhone (3GS and higher models) to find nails in the studs of your drywall, or any sort of magnetic metal hidden from view. This app uses the iPhone magnetometer to find perturbations in the magnetic field caused by a metal.

For best results, point the right edge of the iPhone to scan an area.

Features

⎈ Simple Elegant interface
⎈ Audio feedback for metal detection
⎈ Visual feedback for metal detection.

For best results...

⎈ Hold the right edge of the iPhone (while facing the screen) towards the wall.

⎈ If your device has a external case, please remove before using this app.

⎈ If the app starts beeping randomly--even when not near a metal object--try to calibrate magnetic interference by waving your iPhone in a "figure 8" pattern a few times.