In Washington DC, we aren’t lucky enough to have city wide wireless Internet. So… I thought i’d try and shut off the WiFi on my iPhone and see what happened.
It dramatically increased the battery life on my phone. This wasn’t a very scientific study but just an observation that I had today.
Have you had similar experiences? Any iPhone tips you wanna share?
Oatmeal Stout - Justin Thorp's blog 
Yes, agree with that….
Turn off bluetooth as well if not used, that might also help.