Here are the steps that has to be follow in-order to quit a background application.
The first step require you to quite an app from running in the background, You simply need to double press the Home button to bring up the multitasking menu.
Now press and hold any icon until it wiggles. Then press the delete badge at the top left of an icon to end the application.
When done press the Home button to complete the action.
This is a basic tutorial and is being provided as reference to those new to the iPhone, iPod touch and unfamiliar with its technology.