The Home button (See Image -
) is one of the iPhone’s few physical buttons. It is located on the front of the iPhone below the screen.

If you’re in an app, clicking it will quickly jump you back to the apps Home screen. If you are paging through your sixth Home screen of iPhone applications, pressing the Home button will always take you to the first Home screen. From the first Home screen clicking it again will take you through to the Search page where you can search through all of the data on your iPhone.
By double-clicking the Home button you will enter the multitasking interface. From here you can view and close multitasking apps, lock the screen orientation and operate your iPod. For more information on Multitasking click Here.
If you press and hold the home button the Voice Control screen appears and you hear a beep. This app lets you make phone calls and control iPod music playback using voice commands. For more information on Voice Control click Here.