This affects the iPhone 4 and iPhone 3GS users running iOS 4.1. It’s almost too easy.
- Hit “Emergency Call”
- Dial ### and press the call button (any non-emergency number technically works)
- Immediately press the lock button on the top of the iPhone
- You’re now in the users address book.
From here you can make calls, browse the address book, access to the camera, email, MMS, and photos, including the ability to email or send MMS pictures from the photo library. The method does not work on the iPhone 3G.
Apple will patch this with the upcoming iOS 4.2 update, so this won’t last too long.