There are multiple feature-rich applications that can help you open and edit .pps files while working on Mac OS X. Two of the best known applications are NeoOffice and OpenOffice. Everything you need to know about the first one is at the following link http://neooffice.mac.informer.com/ while the second one can be found at this address http://openoffice.mac.informer.com. These two applications will allow you to save your files in different formats.