Viewing and Changing Your iTunes Store Account Information
You can look at and change your iTunes Store account information any time you want. For example, you can change your account information if you move (and thus, your billing address changes), if you need to switch to another credit card, or if you want to change your password to keep your account secure.
To see your account information in the iTunes Store:
Click the Account button that shows your account name, or click the Account link in the Quick Links panel of the iTunes Store home page.
If you haven’t logged in recently, iTunes displays a dialog box for you to enter your account password.
Enter the password, and then click View Account.
Your account page displays fields for your Apple ID, the last four digits of the credit card that you use for the account, your billing address, your most recent purchase, and your computer authorizations.
You can click buttons to edit your account and credit card information, and also to manage alerts (e-mail messages sent by iTunes about new releases from artists that are listed in your purchase history). You can also manage your iMix playlists and view your purchase history.