Having trouble manipulating Office documents or creating them on the fly? The Open XML Application Programming Interface (API) allows you to effectively work with Open XML packages. Using the API, you can generate and manipulate Word 2007 documents, Excel 2007 spreadsheets, and PowerPoint 2007 presentations using a few lines of code. Plus since it uses managed code, so it's safe for many server-side scenarios.
Here are a few useful links and resources:XML in Office Developer Portal
Office Open XML Formats Resource Center
Doug Mahugh: http://blogs.msdn.com/dmahugh
Eric White: http://blogs.msdn.com/ericwhite/
Brian Jones: http://blogs.msdn.com/brian_jones/
Wouter van Vugt: http://blogs.code-counsel.net/Wouter/