Here are a couple of really interesting tools that came up in conversation yesterday:

• Wouter van Vugt's Package Explorer for trawling through the OpenXML in the cool new document formats
• OpenXML4J, an Office OpenXML file format java library
• PHPExcel classes allow you to work with Excel files from PHP
• Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats - which allow versions of Office all the way back to Office 2000 to read and write in the new file formats.

 I think that these tools show that you don't have to be a hardcore .NET developer to take advantage of OpenXML.