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. [more]

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.