I just did this with Outlook 2002. Open Outlook. Chose "tool", "form", and
then "design a form". Open the type of outlook item you want to restrict.
In this case it would be an email. So click on "message". A template will
appear that looks like you can design it (which is what you are doing).
Click on the "actions" tab. You will have 4 options on the lower section:
"reply", "reply to all", "forward" and something else that I can remember
right now. Select the action you want - in this case "forward". A dialog
box pops up, and uncheck "enabled" (upper right corner of the new dialog
box). Click on "file", "save as", and give the template a name you can
remember. The file will not be saved in Outlook, but it will generate an
Outlook item. I have saved these on my personal section of the server. Then
chose "file" and "close". When it asks you to save the changes, say "no".
When you want to create an email that no one can forward, then go to this
file and open it. It will look exactly like one of your regular emails.
When someone receives the email message and tries to forward it, they will
receive a message to the effect of "this feature is not available".