Step 1:  open Outlook, and click on tools->accounts

Step 2:  click Add->Mail

Step 3: Enter your name as you would like it to appear in the from: field of all outgoing mail.

Step 4:  Enter the email address which the others will use to send email messages to you.

Step 5:  Incoming(POP3) server: mail.yourdomain.com
            Outgoing(SMTP) server: mail.yourdomain.com

Step 6:  Account username: account@yourdomain.com (not just account!!!)
             Password: ***********

Step 7:  Click Finish.

Step 8: Now click once on the newly created account, and choose "Properties". Go to the 'servers' tab and check my server requires authentication. The Settings tab will be highlighted. Click on Settings and select 'log on using'. Enter account name 'account@yourdomain.com' and password ***********. Click OK.

Step 9: If you want the messages to be kept on the server, choose the 'advanced' tab and check 'leave a copy of messages on server', click OK.

Step 10: You are done!