I found the coolest tool for presentations today, it is called ZoomIt and it's Free :)
See a video of it...
you can download it here...
What this does is turn your computer screen into a sort of white board application that can be used with a mouse or on a tablet pc.
I also tested a wireless solution for showing your desktop on a big screen TV. It is called Warpia and it is very easy to install and use. Here are two videos...