How to switch the data between two iphones? - 1

With two iphones on the same account, how can I switch the data like the contacts, apps, and pictures between the two phones. Like move my brothers data to my phone and all my data to my brother's phone. We just want to switch the devices but keep all of our same stuff.

Sync each of your iPhones to the iTunes account and then sign into the other account that you're wanting to sync things to and restore the iPhone from the most recent back up then that will put each other's things on the devices.

I have an iPhone 4 and my wife has a 4s. We want to trade phones. Once we get Verizon to reassign the phone numbers, what's the easiest way to migrate the apps, settings and data between phones? BTW, the 4 syncs with iTunes on windows 7 and the 4s is paired with a OSX Lion machine.