If Santa brought you or your child a new iPod or iPad for Christmas then you will definitely want to enable it's parental controls.
Even if it's yours and not your child's iPod you might want to turn off the in-app purchase feature. One of my family members ended up with a bill for several hundred dollars worth of in-app purchases because this feature wasn't locked down and a child got a hold of the iPod and racked up a bunch of in-app charges. In-app purchases are how many "Freemium" app developers make their money. They make the game free to download but charge for additional content. Even kids that aren't old enough to read can end up buying things in the app without anyone knowing it until they get the bill.
Check out the article linked above to learn how to turn this feature off completely. Did your child accidentally buy s huge amount of in-app merchandise? Let us know your own in-app purchase horror story in the comment section below.
Just discovered $820 worth of in app crap
Not sure which game or which child
Scamming just stooped to a whole new level