iPhone and iPod touch have an internal rechargeable battery. To charge the battery, choose one of the options below:
Connect the device to your computer (not your keyboard) using the included cable to charge the battery and sync. Your computer must be turned on and not in sleep or standby mode. If the device is connected to a computer that’s not turned on or is in sleep or standby mode, the battery may drain.
Connect iPhone or iPod touch to a power outlet using the included cable and a USB power adapter to charge the battery.
Note: iPhone 3G, iPhone 3GS, iPod touch (2nd generation), and iPod touch (3rd generation) do not support FireWire and will not charge from any FireWire-based power source. If you connect either of these devices to a FireWire-based charger or accessory, you will receive the alert screen below:
"Charging is not supported with this accessory."