Repairs Universe demonstrates how to replace the battery on an Apple 3G iPhone. First, remove the SIM card and remove the two screws from the bottom of the phone. Next, use a safe pry tool and run it along the phone between the bevel and the glass to pop out the screen. Then, slowly lift the glass. It will still be connected to the phone body with three ribbon cables. Popup the connectors on the cables one and two. Pop out the three connector from its jaw connector. Remove the digitizer glass from the Phone body. Release the pop connects four, five and six. Use a philips screwdriver to remove the seven screws around the perimeter. Next, remove the motherboard from the phone with the safe pry tool. It will be attached to the camera which can be removed with the pry tool. You will now have access to the battery. Remove it with the pry tool and replace it.