I've created an app exclusive to iPhone 3GS and it's finally on sale! Follow me on Twitter @garywkfung for a chance to win a FREE copy of iMetal. iMetal is a metal detector using the compass as a sensor - check out the video demo at www.imetalapp.com Using iMetal: 1) Calibrate iMetal by shaking your iPhone 3GS in an area free of metal objects. When iMetal reads "Ready", you can can begin scanning. 2) Place iPhone 3GS over metal objects. The sidebars will increase relative to the strength of the magnetic field. 3) When a strong magnetic object is detected, iMetal will vibrate and sound. Hope you guys like the app! REVIEWERS: If you would like to review this app, please contact me for a promo code.