With the release of iOS 6 Beta 3 for developers this Monday, Apple announced in the change log of it that they are introducing @iCloud.Com Email Addresses for the users with their Apple IDs. This is just the Beta release by Apple for @iCloud.Com E-Mail Addresses. The change log stated that the new users signing up for an E-Mail account will be provided with the new @iCloud.Com E-Mail Address instead of @Me.Com one.
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.
Those users who are already having an E-Mail id on @Me.Com will be converted to @iCloud.Com E-Mail IDs when the Beta Testing is done.
Apple discontinued the MobileMe service as of June 30 because of iCloud.com. Apple announced iCloud with their new iOS 5. Apple has integrated their MobileMe services with iCloud.com. As for now people can access MobileMe.Com for a limited time. Apple will be shutting down the service completely soon.