I used to get easily a day's use on my 3GS with iOS3. Now I've upgraded to iOS4, the battery is flat before I get to midday - it runs out FAR quicker. Anyone else noticed this? This is not good - if I'm away from a charger for the day, the phone isn't going to make it. I'd rather lose multitasking (or whatever's draining it) & get more life .. Thoughts?