How you you unlock an iPhone 4?

Hold down the top lock button and the home button down until the Apple sign comes up on ur phone, once this comes up release the lock button at the top but still hold the home button until the connect to iTunes screen comes up, once that screen comes up continue holding the home button and insert the iphone cable to connect it to iTunes, once connected let go of the home button and iTunes will register the phone. Click restore phone, this takes a while but it takes the passcode etc off