Preview at WWDC likely in June, followed by September launch.
Apple Rolling Out iCloud.com Email Addresses with iOS 6 Beta 3
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 beta 3 will receive an @icloud.com email address that matches their @me.com address.Apple discontinued MobileMe in favor of iCloud as of June 30, although MobileMe users are still able to transition their accounts to iCloud for a limited time.
MobileMe and its me.com addresses were themselves transitioned in 2008 from mac.com addresses available under Apple's previous iTools and .Mac services, with MobileMe users able to send and receive email from mac.com and me.com versions of their addresses using either account.