Now that I moved outside of AT&T coverage, I am considering whether I should trade my 8gb iPhone for a 32 gb iPod Touch. However, battery life is a major concern for me. Although there have been rumors that the 32 gb iPod Touch has improved battery life, I don't think its been confirmed. Based on estimates on Apple's website, it appears that the iPhone would get better battery life than the iPod Touch if it were not for power being taken for the phone aspects of the system. (iPhone = 7 hrs of video vs. 5 hrs for the iPod Touch.) I want to conserve as much power as possible and prevent unneccesary battery usage. However, I also don't want to constantly be switching between Airplane Mode and regular mode. (There is no way to turn off the phone component of the iPhone while keeping Wifi on. You have to go into Airplane mode, which is annoying.) Therefore, I took out the SIM card, and it now says "No SIM" in the upper left all the time. I have not been able to do any scientific tests to see if this has improved my battery life. Has anyone checked into this to see if this basically has the same effect as turning off the phone? Any other ideas for extending battery life on an iPhone that doesn't need the phone service? Thanks.