I have had my iPhone 4 now for over a year with zero issues until I recently upgraded to iOS 5. Now every now and then the phones battery will get sucked dry within 1-2 hours without notice. I have also noticed that when it's rapidly draining out the battery the phone is VERY hot to the touch. This would suggest that something is actively running and that is what kills the battery. I can't yet prove this but I'm suspecting the new notification system as the culprit as when this fast battery drain takes place I think I always have one or more notifications on my lock screen. Anyone else.....?