Microsoft has decided Office 12 will be named Office 2007.
Additionally, all programs now have the Office brandname in them. It's not Microsoft Word and Microsoft Excel anymore but Microsoft Office Word and Microsoft Office Excel.
I also saw Exchange 12 as Exchange 2007, this might change to Exchange 2008 cause it will be released in Q1 2007. On the other hand marketing would like to see the names in sync. Nice detail is that the binaries for Exchange 12 are 8.0 while Exchange 2003 are 6.5. 7.0 had codename Kodiak and was cancelled.