Microsoft PowerPoint Exercises
1. Check out the Microsoft education page for tutorials and sample files that you can download.
Five skills (adding text, graphics, creating hyperlinks, animation and applying Word functions) are explained (using PowerPoint) followed by a practice exercise for each one.
This PDF file contains exercises specifically meant for PowerPoint XP, but they can easily be used with earlier versions too.
Exercises start from the basics and are suitable for people with no previous experience with PowerPoint.