1. Back up your iPhone to your iTunes library. Connect it to your computer using the supplied cord. Launch iTunes and select the iPhone under "Devices" on the left. Right click; then choose "Back up."

2. Launch Isohunt in your browser. Use the search box on the homepage to locate an application for jailbreaking the iPhone. Download and save the application to your computer. When choosing an application, look for one that is appropriate for your iPhone model and one that can be used on your PC or Mac. You can find out what model you have by tapping "Settings" "General," "About" and then "Model" on your phone.

3. Check the requirements listed for the jailbreak application. The application will specify which version of iTunes and iPhone software you need to complete installation. You may have to update both. To update your iTunes software, click "Help" from the main menu, and then "Check for Updates" from the drop-down menu. If a new update is available, a dialog box will appear asking you if you want to download it. To update your iPhone software, select the iPhone under "Devices" in iTunes. Click the "Summary" tab to see which version of the software you currently have installed. If the jailbreaking application calls for a newer version of the software, click "Check for Update" to download it.

4. Run the jailbreak application and follow the on-screen instructions. The application will take a few minutes to complete. Disconnect the iPhone from the computer when finished.