PowerPoint/Keynote/Google Presentation
Overview
Applications like PowerPoint, Keynote and Google Presentation are designed to create a sequence (often referred to as a "stack" or "deck") of "slides." These slides can contain, text, images, audio and video.
Quickstart
There is good online document of all these applications. For information on how best to use these tools in presentations, see:
How Do I...? > Presentations > Create a Presentation
Powerpoint
Custom Gudes > Quick Reference
Lynda Tutorial > Movies > PowerPoint
PowerPoint is available for both Macs and PCs, but there are difference, particularly with respect to audio and video. For more information on these differences, see:
OfficeHelpForMac > PC to Mac and Back
Keynote
KeyNote is a Mac only desktop application. KeyNote can import and export as PowerPoint and PDF
Google Presentation
Google Presentation is a web application that is part of Google Apps. As such it works the same on Macs and PCs. Presentations created with Google Presentation can also be downloaded in PowerPoint and PDF format