Open XML Object Model
One of the advantages of Microsoft Office 2007 is the file is in Open XML format. That means the developers can edit the file content easily using program code. Microsoft has put the SDK, Microsoft SDK for Open XML Formats for download. This SDK is July 2007 Technical Preview. The developer can download the SDK and play with the code in the article, Manipulating Excel 2007 and PowerPoint 2007 Files with the Open XML Object Model part 1 and 2. The examples in this article are for Excel 2007 and PowerPoint 2007. I will post the Word 2007 here once I found it.