Apple iPhone/iPhone 3G (User manual) - Manual (Page 103)

Chapter 8 Settings 103
Get a voicemail message 
Get an email message 
Send an email message 
Have an appointment that you’ve set up to alert you 
Lock iPhone 
Type using the keyboard 
Brightness
Screen brightness affects battery life. Dim the screen to extend the time before you
need to recharge iPhone, or use Auto-Brightness.
Adjust the screen brightness: Choose Brightness and drag the slider.
Set whether iPhone adjusts screen brightness automatically: Choose Brightness
and turn Auto-Brightness on or off. If Auto-Brightness is on, iPhone adjusts the screen
brightness for current light conditions using the built-in ambient light sensor.
Wallpaper
You see a wallpaper background picture when you unlock iPhone. You can select one
of the images that came with iPhone, or use a photo you’ve synced to iPhone from
your computer.
Set wallpaper: Choose Wallpaper and choose a picture.
General
The General settings include date and time, security, network, and other settings that
affect more than one application. This is also where you can find information about
your iPhone, and reset iPhone to its original state.
About
Choose General > About to get information about iPhone, including:
Name of your phone network 
Number of songs, videos, and photos 
Total storage capacity 
Space available 
Software version 
Serial and model numbers 
Wi-Fi and Bluetooth addresses 