Here is a part of their announcement:
As a part of our ongoing deep integration with Exchange Server 2007, we are also unveiling Forefront Security for Exchange Server SP1 Beta 2. This Service Pack integrates multiple scan engines from industry-leading security firms into a comprehensive, layered solution, helping protect your Microsoft Exchange Server messaging environments from viruses, worms, spam, and inappropriate content.
Read more here.
Microsoft, Exchange, Server, Exchange Server 2007, Beta, Service Pack 1 Beta 2, Excahnge Server 2007 SP1 Beta2, Microsoft Forefront, Security, Knowledgebase
Source:? Exchange Team Blog