You will need
  • - iPhone Explorer, iPhone Folder или iPhone Browser;
  • - Summer или Winter Board.
Download the program iPhone Explorer from official website and install it on your computer using iTunes. The utility allows you to see the file system of your phone and perform certain actions.
Download the required set of icons for applications from the Internet. Best download with forums dedicated to the device. There are often each set is supplied complete instructions for the installation, because some files have a non-standard extension or have their own peculiarities. File icons for iPhone usually has the extension .png.
Connect the phone to the computer. Navigate to the folder where is installed the application that you want to replace the icon ("/Apps/").
Look for a file with a name similar to "Icon@2x.png" (in the case of the iPhone 3GS the file will be called Icon.png). Replace it with the downloaded icon. For smartphone iPhone 4 the icon should have size 114х114 pixels, while image apps in 3GS and earlier models have a resolution of 57x57.
Restart the phone. Icons installed.
In the AppStore there are many programs that allow you to change the theme of your smartphone, and change icons. The most common are simple apps Summer Board and WinterBoard, which allows using its settings to download themes through the official mirror and install them directly from your phone. For changing the icons responds to the item "Theme Icons" window. After setting the appropriate switch in the "ON" position the icons automatically replaced with the image of the selected theme.