before setup your outlook 2007, pls make sure you have below information
incoming mail server : mail yourdomain.com
outgoing smtp server : smtp.yourdomain.com
email address : username@yourdomain.com
password : *****************
Open Outlook 2007.
Click the Tools menu, and select Account Settings.
Click on the Email tab and click on the New... button.
Next select Microsoft Exchange, POP3, IMAP or HTTP and click Next.
On the Auto Account Setup window check the Manually configure server settings or additional server
types and click Next.
NOTE: not support this feature on our mail servers, so you should not use the Auto Account Setup feature.
Select Internet E-mail option and click Next.
Fill in the following fields: (for example only)
User Infomation
Your Name : John Smith (for example)
eMail Address : jsmith@yourdomain.com
Server Information
Account Type : POP3
Incoming mail server : mail.yourdomain.com
Outgooing mail server (SMTP) : smtp.yourdomain.com