Hi,
These are the steps to be done.
installing Exchange 2007 Anti-spam system
- Close the EMC (Exchange Management Console).
- Open the PowerShell and navigate using the following path: "Program Files\Microsoft\Exchange Server\Scripts".
- Run the "install-AntispamAgents.ps1" script as shown in window (with ./ before the script name) below:

- Restart the "Microsoft Exchange Transport" service in order to apply configuration changes.
- Open the Exchange Management Console, and on the Organization configuration list, select Hub Transport. The "Anti-Spam" tab has been added to the Hub Transport properties.

Uninstalling Exchange 2007 Anti-spam system
If from some reason, you would like to uninstall the Anti-Spam system from the Hub Transport role, follow the next steps:
- Close the EMC (Exchange Management Console).
- Open the PowerShell and navigate using the following path: "Program Files\Microsoft\Exchange Server\Scripts".
- Run the "uninstall-AntispamAgents.ps1" script as shown in window (with ./ before the script name) below: Note:
You will be prompt to disable and then uninstall each agent of the
Anti-spam system like the Connection filtering, content filter, Sender
filtering etc.

- Restart the "Microsoft Exchange Transport" service in order to apply configuration changes.
- Open the Exchange Management Console, and on the Organization configuration list, select Hub Transport. You will see that the "Anti-Spam" tab has been removed from the Hub Transport properties.

For more information refer below links,
http://www.petri.co.il/install-anti-spam-exchange-2007.htm
http://exchangeinbox.com/article.aspx?i=104
http://technet.microsoft.com/en-us/library/bb201691.aspx
Hope this will help you.