The front surface of the Apple iPhone has only one button -- the Home button. Pressing the Home button takes you to the main screen of the iPhone's graphical user interface, where the pre-installed Apple applications are housed when you first get your phone. You simply swipe from right to left or vice versa to change pages and access additional apps. From any screen, you can also choose from the device's four primary functions using icons at the bottom of the screen. By default these are: Phone: This app allows you to add contacts, check voice messages and make calls via a host of networks including 3G, GSM or EDGE cellular phone service. Additional network capabilities have also been added to latest phones.Mail: The Mail app allows you to send and receive e-mail via POP and IMAP, and includes in-line picture, HTML and push e-mail capabilities. Since iPhone 4S, voice dictation is also included.Safari: This is the built-in Web browser that has come with all iPhone OSes.Music: Formerly called the iPod app. Despite the name, Music allows you to store and play not only music, but also audiobooks and podcasts from your playlists