PPS files are created by Microspft Powerpoint and to open them you need to install Microsoft Powerpoint (which you have to pay for) or a Powerpoint Viewer (which is free and can be download from the Microsoft web site).
I believe it is possible to "save" a powerpoint presentation in a web based (HTML) format so it CAN be viewed in IE.
But if that is done then the extension is no longer PPS.
You don't need to have MS PowerPoint installed in order to view .pps files.
These are You don't need to have MS PowerPoint installed in order to view .pps files.
These are what MS term slideshow files and they can be viewed by downloading the free PowerPoint Viewer from the MS main site. The other option is to use the free OpenOffice.org office suite.