Just for the record, Blackberry phones -- which all have supposedly battery-eating "push" email services -- can last three to four days on a charge. That's days -- not hours.
One of the reasons for that is that GSM Blackberrys -- as well as the original iPhone -- aren't 3G devices. They run on 2.5G EDGE data networks. EDGE uses much less battery power than 3G.
But Apple wants to sell lots of their newly redesigned phones all over the world. That includes places that skipped over 2.5G/EDGE networks and went directly to 3G.
Is a 3G iPhone actually faster than a 2.5G iPhone? On paper, yes. In some areas, where you receive a good 3G signal, yes. But, in a number of tests with friends and also with people standing online at Apple's SoHo store on Sunday morning, speed differences are barely noticeable.The phone is faster using a Wi-Fi connection. That's why the iPhones keeps asking if you want to join nearby Wi-Fi networks. But, if you don't need Wi-Fi turned on, you should turn it off. Many other smartphones do that automatically to extend battery life. Some original iPhone owners waiting on line said they keep their Wi-Fi turned off except when absolutely necessary. Bluetooth and especially GPS services are also a drain on battery life. With nearly all data radios turned off, except for the 2.5G/EDGE services, and with light use, the iPhone test handset was able to get 12 to 13 hours out of the battery before being warned to recharge (20% remaining). That comes close to getting you through an average day.