Apple Keynote (part of Apple's iWork suite of productivity apps) is a fantastic presentation tool! In terms of quality and graphics (let's face it, those are pretty critical when giving presentations), it blows away the competition (ahem, PowerPoint). Anyone who is serious about giving high-quality presentations uses it (if not, you should).
One of the really cool features I love about Keynote is the ability to automate a presentation. For example: you have a slide deck that you want to distribute to many people in many different locations. Rather than giving the same presentation over and over again (or even using something like GoToMeeting, which I also love), we can use Keynote to completely automate the presentation (including YOUR voice narrating the slideshow). At the end, you simply send the recipients a video file to watch.
Here's how it works:
First, you need to build your slide deck in Keynote (or import into Keynote from PowerPoint). Once that's done, find a quiet place where you can be alone (since you will be recording your voice as you "present" your slides), preferably with a good microphone. When you're ready, go to File | Record Slideshow in Keynote. You will see a screen like this:
At this point, it's time to start recording your slideshow as if you were giving it live (as you do, you will see the audio meter adjust with your voice). As you record your voice and advance the slides, Keynote is keep track of it all, so by the end, you're left with a completely automated slideshow. All you have to do is export as a video and send.
Very cool stuff!