Mark Russinovich has built a tool called Zoomit.exe with which you can zoom into the screen fast.
It’s got these additional features:
* From Vista on, it does even live zoom.
* You can draw lines, straight lines, rectangles, ellipses.
* You can write text.
* The tool has been built as support for presentations, so it’s got a break function.
Though I use it only for zooming, I like it.