For those of you who haven't upgraded to Office 2007, there is a way to use Office 2000, 2003 or XP to open Office 2007 documents. Microsoft has released the Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats. Download and run the installer from http://www.microsoft.com/downloads/details.aspx?FamilyId=941B3470-3AE9-4AEE-8F43-C6BB74CD1466&displaylang=en
You will need to have the latest service pack installed for your version of office - SP3 for Office 2000 and XP and SP1 for Office 2003.
I hope this will be useful for you.
--Joey Carabetta