OK, I my wife and I have Iphone 3g's. Her battery is lasting 2 days mine is lasting 6hrs. Only difference is Exchange and some apps. Our use was pretty similar other than I get around 60 emails a day she gets around 7. I understand a difference but that is way too big not to be a software issue. Re-cap of first two days with my Iphone with Exchange - First day - In the office and I could not get the Iphone to connect to Wifi so all I had was 3g and the phone lasted 13hrs with very heavy use. Day Two - Got the WEP to work on the Wifi and the battery only lasted 7hrs with less email and less use than day one. Tweeted about it on Twitter and someone replies that they did a test... no exchange configuration on iphone and the battery lasted 24 plus hours... with exchange 6 hrs So it seems Exchange is killing the battery's on the Iphones, and maybe 3g is better than Wifi, or at least WEP wifi. ( I have non-wep wifi at home and it seems to last forever for my wife?) I will test no Wifi again tomorrow and see what happens. Anyone else notice the same thing. Did not see any battery/Exchange postings already.