I understand .mac/.me mail will still come through.
iCloud Mail setup, do not choose .mac or MobileMe as type, but choose IMAP...
On second step where it asks "Description", it has to be a unique name, but you can still use your email address.
IMAP (Incoming Mail Server) information:
• Server name: imap.mail.me.com
• SSL Required: Yes
• Port: 993
• Username: example@me.com (use your @me.com address from your iCloud account)
• Password: Your iCloud password
SMTP (outgoing mail server) information:
• Server name: smtp.mail.me.com
• SSL Required: Yes
• Port: 587
• SMTP Authentication Required: Yes
• Username: example@me.com (use your @me.com address from your iCloud account)
• Password: Your iCloud password
•
Also, you must upgrade your password to meet the new criteria: 8 characters, including upper and lower case and numbers. If you have an older password that does not meet these criteria, when you try to setup mail on your mac, using all of the IMAP criteria listed above, it will still give a server error message. Go to http://appleid.apple.com then follow directions to change your password, then go back to setting up your mail using the IMAP instructions above.
Thanks to dpepper...
https://discussions.apple.com/thread/3867171?tstart=0