That's why I own a jailbroken iPhone. RecognizeMe is a new Cydia tweak which lets use front-facing in iPhone 4 or iPad 2 to unlock your iPhone. Yes, it's really working. The tweak comes from developer Apocolipse behind the popular tweak 3DBoard. The tweak has been submitted already to Cydia store and will be available in few days.
RecognizeMe is the first Facial Recognition security for the iPhone. Although not perfect, RecognizeMe does a pretty good job at facial recognition, given optimal conditions. RecognizeMe sits on the iPhone passcode screen, so it serves as an alternate to, rather than a replacement for the passcode.RecognizeMe uses 2 2 different algorithms to verify, one is good for accessing 3d biometrics, the other is good at weeding out? false positives based on feature analysis. This tweak'll be available for $6.99.
Here's a video showing it in action: