Since the release of Office 2007, more and more people are sending around docx and other Office 2007 files. While it is better to have Office 2007 so you can edit all the new smart objects and other neat things, you can use the Microsoft Office Compatibility Pack to at least read them and perform some basic changes to the files.
The 2007 Microsoft Office Compatibility Pack lets you open, edit, and save files in the new file format used by the 2007 Office system. Even if you haven’t upgraded to the 2007 Microsoft Office system yet, you can enjoy some of the benefits of the new Open XML Format including:
- Smaller file sizes
- Improved file recovery
- Direct access to file contents such as charts and comments
The Compatibility Pack lets you exchange files easily between different Microsoft Office releases including Microsoft Office 2003, Microsoft Office 2000, and Microsoft Office XP.
http://www.microsoft.com/canada/compatibility
You can also download the Compatibility Pack directly from Microsoft here: http://www.microsoft.com/downloads/details.aspx?FamilyId=941B3470-3AE9-4AEE-8F43-C6BB74CD1466&displaylang=en