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.