This is Rooting guide if you do not have a computer, or if the phone has a problem connecting to the computer through USB port. If you have access to computer, you can use various tools such as SuperOneClick to root the phone.
- Download the tool z4root to the micro sd card.
- Download AppInstaller from Android Market in order to install non-market apps
- Insert the micro sd card in Samsung Galaxy S Captivate/Vibrant and use the AppInstaller to install the z4root app
- Run the app z4root on the phone. And choose Permanent root