Can I stop iPhone iOS apps from running in the background?
Apps can be designed to run in the background on iOS 4. Some users have reported battery drain or other issues and they suspect some apps might be the culprit. Icons for recently opened apps appear in the fast app switching (or multitasking) dock.
Apps can't be prevented from running in the background, however you can quit them by following these steps:
1. To access the dock double-click the Home button.
2. Swipe left and right to see all of the icons for recently used apps. Some of these may be running in the background. Others are in a suspended state.