Got my iPhone 3GS on launch and just signed up for MobileMe yesterday. Last night I left my phone to charge, so by the time I woke up, the iPhone had a full 100% charge. I listened to music for about an hour at the gym (I don't have data so it couldn't have even used MobileMe at this time). I then browsed the web for about half an hour to an hour on it at home. During this time, I was connected to wifi and push was on. It's been a couple of hours since then and I've left it on sleep and it's gotten about 10 emails and I'm at 20% battery life! What do you guys think the reason is for the huge battery decline?