Ecma has published an updated draft of the spec for the Office Open XML Formats Standard. Here's a link to it:

http://www.ecma-international.org/news/TC45_current_work/TC45-2006-50.htm

This is great news for Open XML developers. The updated draft has a lot of great new documentation, covering things in much more depth than the previous draft. And there is a mechanism for providing public feedback, so you can participate in the evolution and definition of the standard even if you're not part of an Ecma member organization.

Brian Jones has an overview of the draft on his blog, and he also went into more detail in this post. Doug Mahugh has posted an overview of the document here as well.

Check out the spec, give Ecma your feedback, and post your questions, comments and observations right here at OpenXmlDeveloper.org.