Battery Life Do you know how long the iphone's battery lats?

1. Turn Screen Brightness down to less than a half and turn on Auto Brightness. (Settings - Brightness).

2. Turn off Location Services when you are not using a GPS dependant App. If on a long journey using the iPhone's GPS, only turn the App and the service on every so often. GPS based Apps really eat battery life up!
(Settings - General - Location Services - Off).

3. Turn off Fetch Data. With this feature enabled the iPhone will interrogate the internet or your mail account every so often to fetch data, for example, an e-mail. This drains battery life. (Settings - Mail Contacts - Calendars - Fetch New Data - Push Off).

Or if you really want to keep this feature, just follow the same protocol as above , but instead of switching "Push" off, below that, adjust Fetch Data settings, to fetch on a less regular basis ie Hourly as opposed to every 15 mins.

4. On long journeys when all you need is the iPod functionality, turn Flight Mode on.
(Settings - Airplane Mode Off).

5. Remember to run the battery completely flat every so often. I do it around once a month and then fully charge it again.

6. Turn Bluetooth off.
(Settings - General - Bluetooth Off).

7. For those of us who have an iPhone 3GS or updated software on iPhone, switch on the Battery Percentage for better battery monitoring. (Settings - General - Usage - Battery Percentage On).

8. If you are fairly desperate for battery you can turn off the 3G feature of the iPhone. 3G enables higher browsing speed and better call quality. (Settings - General - Network - Enable 3G Off).

9. Turn Wi-Fi off if not in use. The iPhone will use battery searching constantly for Wi-Fi networks. (Settings - Wi-Fi - Wi-Fi Off).

10. Remember, if you really can't manage with the battery life, you can buy iPhone cases which provide extra battery power.

Good Luck