Guy Kawasaki has a Q&A with Presentation Zen's Garr Reynolds here.
Definintely a good intro to the PZ approach, if a little light for regular followers of the PZ site.

Here's a sample:

Question: How did we get to this place where most presentations suck?

Answer: There are many reasons. First of all, presenting exceptionally well isn’t easy. In fact it’s hard. That’s why we find great presenters—and great communicators in general—so remarkable. They are all too rare. Many professionals simply have never had much practice and just follow conventional wisdom and do it “like everyone else” instead of doing it effectively.

PowerPoint and Keynote are both pretty simple tools, but there has been too much focus on the tools themselves. If people want to learn how to make better slides they should study good books on graphic design and visual communication to improve their visual literacy.

When it comes to designing appropriate visuals, there is a hole in our education. Concerning quantitative displays, for example, very few people have had proper training in how to design graphs and charts, etc. The great master Edward Tufte has written many useful books in this regard.
Link

The new Presentation Zen book