How to view all e-mail messages in plain text format in Outlook 2003 and 2007

Microsoft Office Outlook 2003 and Microsoft Office Outlook 2007 provide a new option named the Read all standard mail in plain text option. This option lets you view all e-mail messages in plain text format. If you are concerned that a virus or some other type of malicious script could execute through HTML or through Microsoft Outlook Rich Text Format ( RTF ), you can use the Read all standard mail in plain text option to display all standard e-mail messages in plain text format. The Read all standard mail in plain text option is for display purposes only. The original e-mail message is not converted to plain text format. 
 http://support.microsoft.com/kb/831607