There have been multiple reports today about increased hacking activity on iTunes. You can easily check if your account has been used without your permission by checking your account history. Here's how:
- Open iTunes.
- Click Store > View My Account (your email address).
- Enter your password when prompted. The iTunes Store opens and displays your account information.
- Click the Purchase History button. Review your account for any unusual activity.
That's all there is to it. If you are seeing any unusual activity, that is, purchases it says you made, but you don't recognize, contact Apple immediately.