This article explains how to sync your iPhone with your computer over Wi-Fi. The information in this article applies to iPhones and other iOS devices running iOS 5 or later, and a computer running iTunes 10.6 or later.
How to sync iPhone/iPad/iPod via wifi
To sync your iPhone wirelessly, you’ll need to use a cable (at least once) to change a setting in iTunes to enable wireless syncing for your phone. Do this once, and you’ll be able to go wireless every time after that.
Connect your iPhone or iPod touch to a computer using USB as you normally would to sync your device. If iTunes doesn’t open automatically, open it.
In iTunes, select the iPhone icon to go to the iPhone summary screen. (iTunes may already be on the screen.)