iOS 6 iCloud Features, Specs, Review:

• When creating an iCloud account, you can use any email-based Apple ID or your existing iCloud account. If you had a MobileMe account that you did not move to iCloud, you can use that Apple ID to sign up for a new iCloud account (none of your previous MobileMe data will be present).
• icloud.com email addresses are now available for iCloud mail users. Users signing up for new Apple IDs, or enabling Mail on their iCloud account for the first time, will automatically receive an @icloud.com email address instead of a me.com email address. iCloud users with @me.com addresses that have been used with iOS 6 will receive an @icloud.com email address that matches their @me.com address.
• icloud.com email cannot be sent from www.icloud.com. Users should use beta.icloud.com at this time if they wish to use a web browser to send email from their icloud.com address.
• @icloud.com addresses will be added within two weeks of first using iOS 6.