Please do not trust any email you receive with the following text:

Hello

You have received an iTunes Gift Certificate in the amount of $50.00
You can find your certificate code in attachment below.
Then you need to open iTunes. Once you verify your account, $50.00 will be credited to your account, so you can start buying music, games, video right away.

iTunes Store.

There is also an attachment called "iTunes_certificate_147"

THIS IS NOT A LEGITIMATE EMAIL FROM APPLE!

The subject heading is usually "Thank you for buying iTunes Gift Certificate!"