How do I temporarily disable iPhone network carrier
I want to disable my cellular carrier temporarily to increase battery life. I already know how to turn off 3G, but I also want to disable incoming phone calls to basically just turn the iPhone into a wifi only device to surf the web for as long as possible without recharging. I suppose I could just remove the sim card, but isn't there a way to achieve what I want through the menu's?
iPhone 4, iOS 4.3.1