said by darcilicious:
All of this is in place?
Whenever the computer and the iOS device are on the same network, the iOS device will appear in iTunes, and you can sync it. The iOS device will sync automatically when all of the following are true:
* The iOS device is plugged in to power
* iTunes is open on the computer
* The iOS device and the computer are on the same Wi-Fi network
Is iTunes installed on a computer that is connected to your network over wifi? If so, "same Wi-Fi network" may mean same access point for both the computer and the iOS device if you have multiple ones at your location (and depending the router and its settings).
If needed, here are the troubleshooting steps: »support.apple.com/kb/ts4062
I'm well aware of how it is "supposed" to work, but it doesn't. There have been many reports of it not working. Google it.