Backwards Compatibility from Office 2007 to Office 2003 Made Easy
By installing the Compatibility Pack in addition to Microsoft Office 2000, Office XP, or Office 2003, you will be able to open, edit, and save files using the file formats new to Word, Excel, and PowerPoint 2007. The Compatibility Pack can also be used in conjunction with the Microsoft Office Word Viewer 2003, Excel Viewer 2003, and PowerPoint Viewer 2003 to view files saved in these new formats.
Click here to download the Microsoft Office Compatibility Pack to convert Word, Excel, and PowerPoint 2007 files into Office 2003 versions.
Click here for an simple explanation of how to open Office 2007 documents in Office 2003 versions of the same applications.