You will need the server settings for your e-mail address. Go to EarthLink Server Settings to get these settings.
Open Outlook, click Tools, then choose Account Settings.
Click the E-mail tab, and click New.
Select Manually configure server settings or additional server types, and click Next.
Select Internet E-mail, and click Next.
Enter the following information for E-mail Accounts:
Click the Outgoing Server tab, select the box labeled My outgoing server (SMTP) requires authentication, then choose Use same settings as my incoming mail server.
Click the Advanced tab.
Note: Port 587 will work on any ISP network. If you have trouble sending e-mail, if all else fails, you can switch to port 25. However port 25 will only work if you are connected to the EarthLink network.