Some free converter from OOXML to ODF format.

Beware of privacy related concerns!

> Do not use them with sensitive data.

> Do not give them your main e-mail address as it could be sold to advertising (spam) companies.

http://www.zamzar.com/

http://media-convert.com/conversion/

http://www.youconvertit.com/

http://www.docx2doc.com/index.aspx

http://www.docx-converter.com/