Neowin has the buzz from “sources close to Microsoft” who say they will be released in late October. Hit the link for the details, but there are 6 versions (8 if you count the “N” versions for the EU) and they are essentially the same as the line up that was rumored last year except that the Windows Vista Enterprise version promised exclusively to Microsoft Software Assurance subscribers is missing. Since that one has effectively been announced already, I suspect its absence is merely an oversight.
Update: Activewin quotes a unnamed Microsoft spokesman as saying the Neowin list is inaccurate.
Update 2/18: Microsoft asked that the Neowin story at the above link be removed, but they now have an update with the apparently final list.