iPhone Theme Store

Works only on jailbroken iPhone and iPod Touch.

iPhone and iPod Touch currently sports the cool looking slide to unlock feature. if you want to protect your phone you could password protect your lock screen.

Android has a cool unlock screen where you can set a pattern on the screen that you draw in a grid to unlock.

AndroidLock is a free new jailbreak iPhone app that brings the Android-like unlock pattern to iPhones.

Just search for AndroidLock in Cydia or Rock and install it. Then go to Settings –> AndroidLock and set your pattern to unlock.

If you forget your unlock pattern, here is what to do (I know I did the very first pattern I set )

• Call your iPhone from another phone
• Answer the call and then Press Home button
• Go to Cydia and uninstall AndroidLock

Now you can re-install AndroidLock and set a new pattern.

Source:
Get Android Style iPhone Unlock Pattern [Jailbreak]