A nasty glitch in iOS 4.1 lets anyone easily access both the phone and photos app on every model of the iPhone. The bug was found by a MacRumors forum member last week, but has just recently received major attention.
To bypass the password protected lock-screen, all you have to do is tap “Emergency Call”, enter a random number and hit call, then quickly press the lock / power button. You will then be booted to the phone app, where you can access contacts, recent calls, and even dial a number. If you tap a contact’s picture ID, you will be taken to the Photos app, where you have full access to view any picture. In this state, neither the home button nor the lock button do anything, and to exit you will have to make and end a call – at which point you will be brought back to the lock-screen.
via iOS 4.1 Bug Allows Access to Contacts, Photos – iPod touch, iPhone, and iPad news – Multi-Touch Fans.