My iPhone started draining the battery fairly quickly by most accounts of battery life, including going from a 100% full charge to the Red Battery Warning in 7 hours with absolutely no physical usage (during the overnight hours).
I tried two things (during the same time) so I’m not sure which was the actual fix but here goes:
1) Let the phone run down past the red battery warning up to the point where it shuts off and becomes unresponsive. Plug it in to charge for a few minutes then use the force reboot (hold down the menu button and sleep button until it resets) to get the phone operable again, then charge until full.
2) My original working hypothesis was that Safari wasn’t shutting down to a sleep state when leaving the browser and going back to the menu. My evidence was, that in my days of usage before getting to my 7 hour drain state, every time I went to Safari, my my.yahoo.com page was trying to refresh. I set up a bookmark for the address of about:blank to create an empty browser page and started loading that prior to returning to the main menu.
The result. I’m now on hour 18 of my latest charge and my battery icon is indicating I still have roughly a 75% charge with normal usage during those 18 hours.
Anyone out there who can help me test in an A/B fashion would be appreciated since my iPhone is apparently fixed.