Macintalk design has an article on giving Keynote presentations on other peoples computers. I'm sure many people have the problem of perfecting a presentation, to have it messed up or incompatible with the computer you are giving the presentation on.

The tips mainly involve converting your presentation to a universal format, like PDF or quicktime movie, and it goes into the details of exactly how to do so.

From the article:

Unless you’re holding a presentation from your own machine, you will run into several problems. This first is that the machine you’re presenting from won’t have Keynote installed, or it won’t have the fonts you need. It might even be running Windows.