A new Microsoft Office, a new Microsoft Office division | ZDNet

Looks like there's a lack of consensus between Mary Jo Foley's sources and Paul Thurrott's sources (with the latter saying May, 2013 availability)

"Microsoft also won't be talking delivery dates today. But my sources -- who were right about the public beta of Office 15 hitting in July -- have said Microsoft's goal remains to release to manufacturing the final Office 15 client, servers and services before the end of calendar 2012, possibly around November."

A new Microsoft Office, a new Microsoft Office division | ZDNet