Mary Jo Foley has some very (very!) early Office 12 details:
According to partner sources who requested anonymity, Microsoft has established an internal Office 12 ship calendar that pegs Office Beta 1 availability for August 29, 2005. Beta 2 is slated for December 5, 2005. The internal release-to-manufacturing target is May 22, 2006. And the target for “street” availability for the Office 12 System is July 17, 2006, the sources said.
Hmmm. It might be a while before my next Office book.