Microsoft is promoting Open XML, a new file format native to Office 2007, as an open standard. But Alan Yates, general manager in charge of Microsoft's information worker business strategy, said the company welcomes the development of Office plug-ins for OpenDocument. "We have always expected that third parties would create bridges between the two sets of XML-based formats," he said.

Edwards said his plug-in currently can save Word documents in OpenDocument while retaining their formatting and other metadata. More work is needed, however, to enable Excel and PowerPoint files to be saved properly in OpenDocument, he said.