Click Tools and click E-mail Accounts

Select Add a new E-mail Account and click on Next

Select POP3 from the list and click Next

User Information:
Your Name: Enter your name -> this is the name your recipients will see in the "From" field of your E-mails
E-mail Address: Enter your E-mail address

Logon Information:
Username: Enter your email address
Password: Enter the password you entered into vpopmail or qmailadmin

Server Information:
POP3: enter then name ip of your server
SMTP: enter then name ip of your server

Click "More Settings"

Click the "Outgoing Server" tab
Place a tick in the "My outgoing server (SMTP) requires authenticaion" box
Select "Use same settings as my incoming mail server
Click Next
Click Finish

Continue to Setting up SpamAssassin