On your black berry you should have an Email settings icon. Open this and log into it. If you don’t already have a login for the mail management page you can create one from that screen as well. (This is a separate login from your phone provider’s webpage, and separate from your mac.com address.)

Once logged in you’ll be able to add your mac.com email address to the phone as an email address for it to check. You’ll need to give it the email address, and password. You may also need to give it the POP3 server name that you would enter into your mail client.