Microsoft announced today that Office 2013, has reached the RTM (release to manufacturing) milestone. The coding and testing phase of the project is complete and Microsoft is now focused on releasing the new Office via multiple distribution channels to customers.
General availability is planned for the first quarter of 2013. Starting October 19, customers purchasing Office 2010 from local retailers or resellers will receive the new Office for free upon availability. Customers will also see a preview version of the new Office on Windows RT devices, beginning with the Windows 8 launch on October 26.
Source: Office Blog