Here is a quick guide to the App Store on your iPhone.
iTunes for iPhone Equals Standard iTunes
Just as with the standard iTunes store on your iPhone, there is a built in App Store application for your purchasing convenience. Instead of just including these as one unit for shopping Apple has decided to split them up on your iPhone because of the limits of the device and the 3G network. In this way the App Store was born, its own part of iTunes that deals specifically with iPhone and iPod Touch applications. The App Store on the iPhone works a little bit differently than it does through iTunes on your computer and you have to be aware of its interface and limitation.
Using App Store Tabs on the iPhone
The App Store works very similar to all iPhone application with a task bar of tabs at the bottom of the screen and the main interactive interface in the rest of the screen. When you open the App store you will already be opened into the first tab, which is called Featured. This is where “featured" applications may be sitting, such as new high profile games and promotional software that Apple has financial stake in you downloading. These applications are rarely free and if they are they are usually an extension of a corporate brand image. At the top there currently is a countdown to the one billion application download for the App Store.
The next tab in line is the Category one that divides the programs into their respective genre like games, entertainment, utility, or reference. When you select one of these you can then look at list of the top paid applications within that genre, the top free applications, and new ones lined up by release date.
The next tab is the Top 25 one and simply lists the top twenty-five most popular iPhone and iPod Touch applications available at the App Store right now. Right next to that is the Search tab that allows you to search the App Store for specific keywords. This works best if you just try to search for words found in the programs name or developer title.
The last one is Updates and lists all of your applications that are ready for updates. In the upper right hand corner there is a button titled Update All that you can press and have updates begin on all applications. Since you are doing this either through the 3G network or a Wi-Fi connection you will not be able to update all as some files will be much too large. For these you will have to plug your iPhone or iPod Touch into your computer and update using the desktop version of iTunes.
App Store Infoshop
When you select an application, you have display screen that will give the summary of the application that you would find in the normal iTunes display, also including the star rating, product information, and links to read customer reviews. From here, you can also press a Tell a Friend button to uselessly email someone about the application or the Report a Problem button to send Apple information about problems with the App Store. In the upper right hand corner of this display will be a button that will either have a price in it or say FREE. When you press this you will be prompted to sign in, then you can press it again to begin the download. Once it does this, the icon for the application will appear in an open spot on your iPhone desktop and a status bar will be on the bottom of it showing you the progress of its download.