What is the tiny black button on the back of my black berry storm for? Its behind the back cover.

New Power / Lock button usage
Using the Power or Lock button on the top of the BlackBerry smartphone, you can perform the following tasks depending on the state of the BlackBerry smartphone:
State of the BlackBerry smartphone: Unlocked and the back light is turned on

Action: Press and release button.
Result: Locks the BlackBerry smartphone and turns off the back light.

Action: Press and hold button.
Result: Turns off the BlackBerry smartphone.
State of the BlackBerry smartphone: Unlocked and the back light is turned off
Action: Press and release button.
Result: Turns on the back light.

Action: Press and hold button.
Result: Turns on the back light and displays the power off prompt.
State of the BlackBerry smartphone: Locked and the back light is turned off

Action: Press and release button.
Result: Turns on the back light and displays the unlock prompt.

Action: Press and hold button.
Result: Turns on the back light and presents the power off prompt.
State of the BlackBerry smartphone: Locked and back light is turned on

Action: Press and release button.
Result: Presents the unlock prompt.

Action: Press and hold.
Result: Presents the power off prompt.