Exchange Server 2003 includes various antispam features that carried over into Exchange Server 2007. But unless you have an edge transport server, you may never see them.
Organizations without an edge transport server can run a PowerShell script from Microsoft to enable antispam agents on an Exchange 2007 hub transport server.
To enable the antispam features, open EMS on your hub transport server and navigate to the Program FilesMicrosoftExchange ServerScripts folder. Then enter the following command:
./install-AntiSpamAgents.ps1
Restart the Microsoft Exchange Transport Service, then open the Exchange Management Console and navigate to Organization Configuration -> Hub Transport. The interface now includes an antispam tab.