The iPhone App Store is a service that allows you to purchase games and other useful applications for the Apple iPhone. The App Store can be accessed through iTunes from a computer or directly on an iPhone. The applications are created by official Apple developers as well as third-party developers who are part of the iPhone Developer Program.

At the March 17, 2009, preview of iPhone 3.0 software, Apple made a number of announcements regarding the App Store. Most significantly, paid applications will now be allowed to "sell" users other applications or updates within the application itself, rather than redirecting them to the official App Store. As well, updated push notification will alert users when applications have new updates in real time, rather than waiting for the user to load that application specifically.

At the time of the official release, clicking on the Buy button in the App Store will immediately purchase the selected application. While many applications are either free or relatively cheap, some can cost as much as $69.99.MacWorld: A heads-up on purchasing things in the App Store (July 10, 2008) New users should take care to click Buy only if they are sure they want to purchase a selected application.

iTunes 7.7 integrates the App Store into the program's interface, but will not show it in the sidebar by default. Go into iTunes Preferences (CTRL + , or Apple + ,) and select the General tab. Place a check mark next to Applications to show your current applications and to access the App Store directly.ZDNet: First look at iTunes 7.7 + Apple App Store and Me.com is live! (July 10, 2008)