iDeviceGuru said:3G doesn't have the light feature either so it's not a standard iPhone app.
The iDevice Guru
Some of these flashlight apps can also show a bright white screen on the device which can provide useful illumination and make them usable on a device without a flash.
The flashlight app I use on my iPhone only affects the flash on the phone and won't work on my iPad. This type of flashlight app is in the minority,however.