Messaging Security Suite includes Antigen for Exchange, Antigen for SMTP Gateways, and Antigen Spam Manager, and provides server-level protection against latest e-mail threats. Microsoft moved "the Antigen release notes, getting started, and deployment information out of TechNet on to Microsoft Download Center. We've left Antigen user guides and best practices in TechNet. Additionally, Evaluation Guide and Quick Start Guide information is all still available in Antigen for Exchange, Antigen for SMTP Gateways, and Antigen Enterprise Manager user guides," stated Microsoft.
Download: Antigen SP2 Documentation