Over the weekend at TechEd, info on Microsoft Forefront (which includes Antigen and Microsoft Client Protection) went live. Consumers and small businesses have products like OneCare and other solutions to help defend their home computers. Forefront provides "a family of business security products helps provide greater protection and control over the security of your network infrastructure."
From the web site:
Microsoft Forefront is a comprehensive line of business security products providing greater protection and control through integration with your existing IT infrastructure and through simplified deployment, management, and analysis. The Microsoft Forefront line of business security products helps provide protection for the client machines, server applications and the network edge.
Here's how the Forefront family fits into the MS product line:
Microsoft Forefront datasheet