You can add up to 3 e-mail alias's... In Mail on iCloud.com, click. in the sidebar, then choose Preferences. ... Click Accounts, then click “Add an alias.” Provide the requested information: Alias: The text you provide becomes the email address ([email protected]). ... Click OK, then click Done.

Go to the mail app and open mail preferences. Then, under accounts, hit the + button. Select "iCloud" and input the log-in information. Select ONLY the mail icon. Then hit "Add Account".

By going through the mail app preferences instead of System Preferences you can avoid dealing with all of the iCloud options. Here is a picture of what it looked like when I added a second iCloud mail account. On the left side in the list of accounts you can see two iCloud icons (boxed in red):

To create a second mail actual account you will need to create a new iCloud account, by creating a new Apple ID at http://appleid.apple.com and then signing into System Preferences>iCloud with it and enabling Mail in the checklist, at which point you will be asked to create a new @icloud.com address.However if all you want is a new email address you can add up to three to your existing iCloud in the form of 'email aliases' - these are additional addresses (not accounts) which deliver into the same inbox as the main account. (In fact it's a good idea to give out alias addresses, rather than the main address, because if they attract spam you can easily change them.)You should be aware before you start that once you've created an alias you cannot turn that address into a full iCloud account or move it to another account.More information on aliases here: http://help.apple.com/icloud/#mm6b1a490a