Via EHLO, The Microsoft Exchange team have created and released a tool (Exchange2007AntiSpamMigration.exe) to allow administrators to migrate some of their anti-spam setting from Exchange 2003 to Exchange 2007.
As stated in the EHLO post the tool can be ran on either Windows Server 2000 or Windows Server 2003 and requires .NET Framework 1.1 or higher to run and an account that has read access to the Active Directory configuration container and access to the MSExchange.UCEContentFilter.xml file.
The download for the Exchange Anti Spam Migration Tool can be found on the URL:
http://www.microsoft.com/downloads/details.aspx?FamilyID=805eaf35-ebb3-43d4-83e4-a4ccc7d88c10&DisplayLang=en