From Sun Microsystems:
The StarOffice 8 Conversion Technology Preview is a plug-in for Microsoft Word 2003 that allows users of Microsoft Word 2003 to read, edit and save import to the OpenDocument Format (ODF). This initial plug-in application will support the conversion of text documents (.doc/.odt) only and full support of spreadsheet and presentation documents will be available in the final version, expected in April. The converter is easy to setup and use, the conversion happens transparently and the additional memory footprint is minimal. Microsoft Word users now can have seamless two-way conversion of Microsoft Word's documents to and from ODF.