If you give a lot of presentations for your job or for school, you might want to build them using the W3C's Slidy instead of Power Point. All you need is a browser and the slides are advanced using the keyboard.
It helps if you know some some basic XHTML markup and CSS, but you don't necessarily have to. Just view the source and you should be able to figure out how things were put together.
The slides are lightweight, accessible, and you won't have to worry about whether or not the machine you are using has Power Point installed.
