To run PowerPoint on multiple monitors, you must have the following hardware
One video board for each monitor
Two or more monitors
In addition, if trying to use multiple monitors in PowerPoint 2000 or earlier, it is a good idea to have software to control both monitors. The two best software solutions for these set ups are
MultiShow Software, by Iosysoft
SundayShow, PowerShow, and PowerKiosk, by OfficerOne (Chirag Dalal, PowerPoint MVP)
If using PowerPoint 2002 or later, you can use the Presenter's view to do the same thing.
In addition, there are two pages on the PPT FAQ about multiple monitors