Download and intstall the compatability patch for Office 2003. It will allow you to view, open edit etc office 2007 docs from Office 2003 without issue. It is better than saving in compat mode. Role it out with GPO will really simplify for you.
Installing the Compatibility Pack
By installing the Compatibility Pack along side of Microsoft Office XP, or Office 2003, you will be able open, edit, save, and create files using the Open XML Formats new to the 2007 Microsoft Office system. Office 2000 users, as well as users of Windows 2000 SP4 and later, can convert Open XML Formats to binary file formats from within Windows Explorer.