Start by checking with your Exchange administrator to make sure you can public a form to the server's Organizational Forms library. If you can't, then you're largely out of luck when it comes to Outlook forms.
Assuming you can, the most elegant approach would be to have two forms --
1) The actual form you want people to fill out, preaddressed to whoever should receive it.
2) A "launcher" form that includes code similar to that at
http://www.outlookcode.com/d/forms/formlauncher.htm
The sample form in the link is a post form, but you could just as easily design a message form to do the same thing and thus to launch the #1 form when the recipient opens it.
Form basics start at
http://www.outlookcode.com/d/forms.htm
--
Sue Mosher, Outlook MVP
Author of Configuring Microsoft Outlook 2003
and Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers