Open XML community !
http://www.openxmlcommunity.org/
We believe that Open XML can help spark an explosion of innovation and investment, which will bring great benefits for customers and the broad ecosystem, in the years to come. We support Open XML becoming an ISO standard.
http://openxmldeveloper.org/
Announced March 21, 2006, the Open XML Formats Developer Group was initially founded by 40 organizations from around the world to provide a technical forum for developers who are interested in using the Ecma International-developed Office Open XML file formats. Membership in the community is open to anyone free of charge to enable broad development with the formats, regardless of platform. Below are further details on the community’s goals, developers who are involved in working with the Office Open XML formats, and quotes about the value of the community and the formats.