See http://www.outlookcode.com/d/newdefaultform.htm

Signature
Sue Mosher, Outlook MVP
Author of
Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers
http://www.outlookcode.com/jumpstart.aspx
> Hello:
> I've created my own custom appointment form. I want this to be the
> default.
> How do I make it the default? Using 2003.
>
> Many thanks,