Those free apps your kids download on the iPod/iPhone/iPad sometimes aren't so free, when they have extra items to make the game bigger and better, but that cost you money, charged through your iTunes account.
Well Apple listened to the parents around the world who'd had rather large amounts of money charged to their credit/debit cards, and there are now restrictions to stop in-app purchases. First make sure you have iOS 4.3 or higher, to check go into Settings, General, About and check what Version is listed, if not 4.3 or higher update using iTunes. Then go to Settings, General and Restrictions and click Enable Restrictions, enter a passcode, then scroll down to Allowed Content and if it's not set to OFF change In-App Purchases to OFF.
Now just be careful the kids don't start making expensive phone calls (Switch your iPhone to Airplane mode)!
