Apple ID Support - http://www.apple.com/support/appleid/ -> Apple ID FAQ -->
"How do I change my Apple ID Name or personal information?
You can change your Apple ID Name at My Apple ID. Select your country and language, enter your desired changes, then click the Continue button. Changes take effect immediately. You can also use My Apple ID to change your personal information, such as your mailing address or email address. See How to change the name you use for your Apple ID if you'd like more information."
When it was posted 6 months ago it quite possibly did work. The instructions to reset the rescue email address now are, from http://support.apple.com/kb/HT5312 :
- Navigate to appleid.apple.com using your web browser.
- Click "Manage your account"
- When prompted, sign in using your Apple ID and password.
- Click Password & Security
- You'll be asked to answer 2 of your 3 security questions before you can make any modifications. If you are unable to remember your answers, you can choose to send an email to your rescue email to reset your security questions.
- After you've validated your identity by correctly answering your security questions, click Edit to the right of your rescue email address.
- Once you've finished editing your rescue email address, click the Save button directly below the email field.
You can't, you will need to contact iTunes Support / Apple to get the questions reset : http://support.apple.com/kb/HT5699
When the questions have been reset you can then change/add a rescue email for potential future use via the above steps.