From Zamzar blog:

Well you can now use Zamzar to convert docx files into any one of the following formats (including older versions of MS Office which only open .doc files):

  • doc – Microsoft Word Doc
  • odt – OpenDocument Text Doc
  • pcx – Paintbrush Bitmap Image
  • pdf – Portable Document Format
  • png – Portable Network Graphic
  • ps – Postscript Doc
  • txt – Text Doc

To convert from docx simply head over to Zamzar, select the docx file you want to convert from your computer and enjoy !

Note: Conversions won’t work for .docx files created with pre-release versions of MS Word 2007.