During the Campus Technology 08 conference I have been using up all my iPhone 3G battery. I did a test yesterday and it saved about 50% of my battery time.

1. Turn off “ask to join networks”. So many wireless access points around here asking me regularly if I wanted to join. I figured this had to be eating up my battery.

2. Turn off “location services”. Only turn it on when I need  GPS.

3. Turn off “push”; turn on fetch every 30 minutes or hour.

Please add any tips you have discovered.