A great read on the topic exists in book format, The Cognitive Style of PowerPoint, by data visualization expert Edward Tufte.

Part of this book is freely available, discussing the involvement of PowerPoint in the Columbia disaster:

http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0...

The entire book is short, and only $7 from the author:

http://www.edwardtufte.com/tufte/books_pp