ZoomIT, is a presentation product that allows you to zoom in on a particular part of the screen during presentations… OR, to enlarge a part of the screen for readability. This was written by the same people who wrote the sysinternals products and is available on the Microsoft download site. I saw it used extensively by many of the Microsoft presenters at TechED 2008.
You can also annotate the screen during presentations by drawing graphics with the mouse or writing text to the screen.
Click here to visit the download page.