These are instructions on how to disable cellular data for specific iOS apps only. You may want to follow these steps if your smartphone plan doesn't include much data or if you're concerned about going over your data for the month.
Tap to launch Settings from your SpringBoard.
Choose Cellular from the Settings menu.
Scroll down the Cellular menu until you get to a section called, "Use Cellular Data For". Here you will find a list of all the applications installed on your device. Tap the switch next to specific application to turn off its ability to use cellular data.
You'll also notice that the amount of data each app has used is listed under the app name. This makes it easy to spot which applications are using an excessive amount of data.