By now it is blogged at various places and the announcement at TechEd 2007 USA hit the internet big. In my opinion the announcement was too important to skip in my own blog. I've seen the first previews for the Open XML Formats SDK in an Office 14 meeting a couple of months ago and that looked really promising and a real improvement for solutions using the Open XML File Format. Instead of having to parse through the XML File Format at a very low level the SDK will provide strongly typed part classes to manipulate Open XML document at a higher level saving you a lot of time when developing.

Check the technical preview out by downloading the Microsoft SDK for Open XML Formats:
http://www.microsoft.com/downloads/details.aspx?FamilyId=AD0B72FB-4A1D-4C52-BDB5-7DD7E816D046&displaylang=en

For an overview of the various other blog locations have a look here:
http://blogs.msdn.com/brian_jones/archive/2007/06/05/more-blogs-on-the-open-xml-dev-tools.aspx