This is the only annotation tool we have found that works with ANY program. The discrete toolbar floats on top of your active program (PowerPoint, Acrobat, Excel, etc.) and lets you annotate with abandon. You can zoom, cover up, highlight, free-form draw and much, much more. As a bonus, it includes one of the easiest to use screen capturing tools.
To see a demonstration of how this product works, please visit the following link: POINTER LINK