iPad/iPhone/iPod touch Tip: Double Tap on Lock Screen to Control iPod Playback

This tip is an oldie but a goodie. It has been available for years and works with every generation and model of iPad, iPhone, and iPod touch. It came to mind because iOS 4’s multitasking ability on the iPhone 4 will leave a lot of apps playing music in the background using the iPhone’s iPod component.
Recent generation iPhone and iPod touch devices have physical volume controls on the side. If you have one of Apple’s earphones with remote controls, you also have a the ability to pause and restart playback. One thing you can’t do, however, is move forward or backward through tracks. And, if you don’t have the remote control earphone, you can’t pause either. This isn’t a problem on the iPod nano or older iPod devices with physical controls for everything. Touch devices have a disadvantage in this respect. This tip will help a bit although it still requires looking at the screen.
If your screen is dark but audio is playing as a background task (even pre-iOS 4 devices can playback audio in the background), double-tapping the select button beneat the display of an iPad, iPhone, or iPod touch brings up the lock screen with album art as the background image and audio controls visible and available for use without even unlocking the screen. You can adjust volume, pause/play, or move forward or backward through available audio tracks. You can shut off the display after making your adjustments. At no point was the screen unlocked to perform any of these functions.