iPhone: Automatic sleep mode
Contributed by qmchenry 
Tagged: Apple iPhone The iPhone can go to sleep at some time in the future with a simple option in timer mode. If you want to go to sleep listening to music on your iPhone, you can instruct your iPhone to go to sleep, too. When the time comes, your music will gently fade and your iPhone will enter sleep mode.
To give you iPhone a curfew, tap the Clock icon on the home screen:
In the Clock screen, tap the lower right Timer icon (if it’s not already selected). The resulting Timer screen will show the Price-is-Right tumblers to set the countdown time in hours and minutes:
Also visible on this screen are the “When Timer Ends” and “Start” buttons. Tap the “When Timer Ends” button and at the top of this list of sounds is a special option, Sleep iPod.
Tap the Sleep iPod option and then tap Set. Review your settings and tap Start on the Timer screen.
You’ll be rewarded with a serious, Mission Impossible worthy countdown timer. When the timer ends, the iPhone will enter sleep mode and your music will stop playing.
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Arjen said on August 6, 2009
Thanks!!! Much better than waking up next to a empty phone :-D
Matt Wilson said on January 4, 2010
The iphone is contantly coming up with innovative solutions to our daily problems. This sleep app is great! I won’t have to go to sleep with my tv on, listening to mobile homes announcers and to cheap pop. wtg apple!
Manufactured Homes said on April 19, 2011
Your comments are spot-on as usual.
AltVader said on November 24, 2011
This is a great workaround for my problem: a broken sleep/power button on my iPhone 4. I only wish I could set the clock, timer, when timer ends sleep ipod to 1 second instead of one minute.
Does anyone know of a timer app which will do this? This would be an acceptable alternative to a $200 out of warranty iphone 4 repair!