The links below are for a few presentations that you may find useful in explaining to others how agile works. Feel free to take them and use them as you wish.
Agile Overview (PP2007 or PP2003) - a basic overview of the tenets of agile and some tips on making it work (based on scrum)
Scrum Overview (PP2007 or PP2003) - a quick once-over of the Scrum process itself
Pair Programming (PP2007 or PP2003) - an overview of pair programming, responses to typical questions and doubts, and how to make it work.
The presentations are designed to be talked to, but should be easy enough to follow. If you like them or have suggestions feel free to leave a comment. Enjoy!