There are a few methods for doing this:

The easiest is to log into your control panel, click on the "POP email accounts", and then click on the autoconfig link next to the account you want to set up in Microsoft Outlook or Outlook Express (assuming you use one of these programs).
This will automatically set up the email for Outlook or Outlook Express.

If this doesn't work, you will need to use the following settings:

POP3 server = mail.yourdomain.com
SMTP server = mail.yourdomain.com

You will need to authenticate in order to send mail through our SMTP server. There is usually an option for this in the email client. You will then need to enter your username and password again. The username has two possibilities. If you are using the default account with the username that you signed up with, you can just enter your username If you set up an extra email account, you will need to use user@yourdomain.com as the username. This prevents confusion if multiple people try using the same user name.