There are 11 tips from Apple for increasing the battery life on the iPhone:
- Turn off 3G
- Minimize use of location services
- Fetch new data less frequently
- Turn off push mail
- Auto-check fewer email accounts
- Minimize use of third-party applications
- Turn off Wi-Fi
- Turn off Bluetooth
- Use Airplane Mode in low- or no-coverage areas
- Adjust brightness
- Turn off EQ
In a nutshell? Use it as an iPod. But not too often.
Agreed… 
Via 43 Folders.
