The iPhone is designed so you can use it without owning a computer, so you have a few options for installing apps on your iPhone without iTunes. You can install apps over a wireless connection using the App Store from your device. If you intend to jailbreak your iPhone, you can add an installer app to obtain third-party apps on the device. Finally, if you still want to use a computer but not iTunes directly, use an iTunes replacement desktop application to perform the app installations. Note that you must have iTunes installed on the computer in order for the iTunes replacement desktop applications to function.

The App Store

The easiest way to accomplish the task of installing apps to your iPhone without iTunes is to access the Apple App Store from the iPhone while on a Wi-Fi connection. This type of installation is referred to as over-the-air. Just tap the “App Store” icon in the iPhone home screen to launch the app. Search for the app to install, and then tap the app’s details page. Tap the price icon, and then complete the payment process to purchase an app. Tap the “Free” icon to download and install a free app. Type your Apple ID, when prompted, and follow the on-screen instructions to install the app on your device.

App Store Considerations

Note that the iPhone must be connected to a wireless network, and you must have a credit card number on file to obtain apps from the App Store. Even if you simply want to download and install a free app, you must have a credit card associated with your Apple account. Additionally, you'll be prompted to enter your Apple ID each time you purchase an app or download a free app.

Installer Apps

You can install apps on your iPhone without iTunes using an installer app, such as Installer.App or Cydia. An installer app runs on your iPhone to enable you to install other third-party apps. Note that most if not all installer apps require that you jailbreak your iPhone to use them. If not done properly, jailbreaking may brick your phone.

Third-Party Desktop Applications

To install apps with a computer but not iTunes, you need a third-party desktop application. Appandora is an iTunes replacement that installs on your computer. Launch Appandora, and then connect your iPhone to the machine using the USB cable. Once connected, you can search the app library for a wide variety of apps for your device. Download the apps you want to install and click the “Download Manager” tab. Click the “Install” button next to each app to install. You can also click the “Apps” tab in the left sidebar and click the check box for each app to install. Click the “Install” button to batch install all selected apps. The Appandora application is available for both jailbroken and stock devices.

CopyTrans Manager is another iTunes replacement application that installs on your computer. You can install third-party applications using the iOS IPA installation package for the application, which you can find on the developer's site. Install CopyTrans Manager and then connect the iPhone to your computer with the USB cable. Click the “Add Tracks” button and browse to and click on the app. Click “Open” to add the app to add to CopyTrans Manager. Click the “Update” button to install the app to your iPhone.