Microsoft and Cisco Systems are merging their network protection initiatives into a joint program that will be released with Longhorn Server in 2007. The initial fruits of their work will be in Windows Server 2003 R2, due out next year.
Digressing for a minute, MS has a very good think going with the Windows Server 2003 "Feature Packs". I wouldn't be too surprised if MS started componentizing Windows Client features in this way, starting with Longhorn or possibly sooner.