I've been playing around with the File Classification Infrastructure stuff in Windows 2008 R2 Server.

I was hoping that you could use it to classify files inside SharePoint 2007. Unfortunately, I couldn't find a way to do it.

FCI works by attaching metadata to a new stream inside the NTFS file system. SharePoint doesn't use NTFS for document storage (instead storing files in the database). (This also means that FCI can't classify files stored on FAT32 file systems such as most USB storage devices)

So as far as I can tell, there's no way to hook the file classification infrastructure up to content already stored in SharePoint. However you could use it to classify files on the file system prior to a bulk migration to SharePoint, since SharePoint picks up the classification metadata applied inside MS Office Files.

Will this capability be included in SharePoint 2010?