Microsoft today released Service Pack 3 for Microsoft Office 2003 (link).
The service pack includes all patches and updates released for Microsoft Office 2003 since SP2. Some notable changes include:
1. Office 2003 programs can no longer open or save certain file formats like PPT created in PowerPoint 97 or before.
2. The Fast Save setting in Microsoft Office Word has been removed.
Here's a guide to slipstream SP2 into your Office 2003 installation CD - the procedure to slipstream SP3 into Office 2003 should be similar though the file names will be different. [the installer is Office2003SP3-kb923618-FullFile-enu.exe]
No new feature is introduced in Office 2003 SP3 expect that it now lets you install add-ins in Microsoft Office Access 2003 on a Windows Vista-based computer.
Once your Office 2003 files are successfully patch with SP3, the version numbers of major executables like Excel.exe, WinWord.exe, PowerPoint.exe should say 11.0.8169.0 while that of Msaccess.exe will be 11.0.8166.0.