Orientation lock – If you've ever tried using your iPhone in bed, then you'll know that the screen often flips annoyingly from portrait to landscape mode as soon as you snuggle down in to your pillow. Apple has thankfully solved this problem with the addition of an "orientation lock", enabling you to keep the iPhone screen in portrait mode regardless of how you're sitting or laying. Double-tap the Home button to bring up the multitasking Dock, and swipe to the left. This brings up music playback controls (which will not only operate the iPod, but any music app, such as Last.fm), and, on the far left of the screen, an arrow icon. That's the orientation lock, and you simply tap it to keep the screen locked in portrait mode. A padlock symbol then appears on the status bar at the top of the iPhone's screen to remind you the display is locked.
