Office ->Save As -> PowerPoint 97-2003
Presentation
Save As .ppt
When you
save a new presentation in Microsoft PowerPoint 2007, you should be
aware that this is a new file format and that companies with a
previous version of Microsoft PowerPoint might not be able to open
or edit your work.
Here are the steps you can take to create a copy in PowerPoint
97-2003.
Try it: Save As Previous Version
Go to Office ->Save As.
Select: PowerPoint 97-2003.
Keep going...
Microsoft PowerPoint 2007 Exam
77-603 Topic: 4. Collaborating on and Delivering Presentations
4.3. Secure and Share
Presentations
4.3.6. Save presentations
as appropriate file types : Save files in .pps format so they
open as a slide show