Exchange 2007 Anti Spam Migration Tool
It is likely that if your running Ex2003 you have spent some time configuring settings for Spam and not looking forwarding to writing the Powershell scripts to convert these settings to Ex2007.
A new tool was posted yesterday that will help enable Administrators convert the settings.
You can download it from here
Overview
The Exchange 2007 Anti Spam Migration Tool reads these settings from Active Directory and converts them to equivalent Windows Power Shell script (consisting of Exchange 2007 tasks) which can then be run on Edge Transport or Hub Transport roles of Exchange Server 2007.