Pretty much every modern version of Microsoft Word should support older WPS format from Microsoft Works and can be used simply open these documents and re-save to ODT format. As for the latest version of Office, the support for old Works formats may eventually phase out.
If you only have access to some previous version of Microsoft Office, you will need to download and install special Microsoft Works 6-9 File Converter that acts as plugin and allows users to open and work with Microsoft Works documents (.wps).
Open source word processors like LibreOffice Writer or OpenOffice.org Writer also may still support Microsoft Works formats and thus should be capable of re-saving the documents to the default ODT format.
Last option for wps to odt conversion would be to get your hands on some old version of Works. It was commonly bundled together with laptops and new computers so you may have some old Works installation CD. In Works you can re-save your documents to DOC or RTF format, which are supported in OpenDocument based programs.Open WPS file Open ODT file
Word processor and text editor from OpenOffice.org suite
Full-featured word processing and desktop publishing tool from LibreOffice suite
One of the most popular word processor program from Microsoft Office suite