My suggestion; I have already experienced confusion in recipents of my e-mails when Apple changed my mac account to mobileme and they started to receive mail from me.com rather than mac.com. I added the following message to my signatures
NOTE: My e-mail address may appear as me.com rather than mac.com. This an alias and NOT a change in address
I have now changed this to
NOTE: My e-mail address may appear as me.com or icloud.com rather than mac.com. These are aliases and NOT a change in address
Now my question. I have an iMac OS X 10.7.5 and have agreed to 'tune in' to iCloud and after a few minor glitches all appears well with Mail etc. HOWEVER I also have a MacBook Pro which I have not upgraded from OS X 10.6.8 because I still have some Power PC programs on it that I have not yet found satisfactory replacements for. My assumption was that the change to iCloud would not affect my using Mail on it. However, although I am receiving mail directed to either mac.com or me.com intermittantly (rule rather than exception) I cannot send mail and get the message "Cannot send message using the server smtp.me.com". If I adopt the edit option to change to either my @me.com or @mac.com it makes no difference. I I adopt the option to try later, it may or may not go but often many hours later. Any suggestions/explanations?