to sync with your itunes over wifi instead of plugging it in directly into your computer.
so, you're computer is upstairs and itunes is open and you want to sync your device but don't feel like going upstairs to plug it in. all you do is connect your device to your wifi network and click sync.
of course you would have to enable to feature first by plugging it in your comupter and click the wifi sync option
Once you connect your phone by cable to your computer, in iTunes there is a setting for "Sync over wifi" check this box and the setting will be established on the phone. From then on when you launch iTunes on your computer your phone should show up under devices if wifi on the phone is on. Now you may find that this dosn't always work. In iOS 5 this worked all the time for me, now in iOS 6 it sometimes does, sometimes doesn't. If it doesn't I find that it helps to close iTunes on your computer, cut the phone on, and then relaunch iTunes on the computer. It should show up then.