Here is a link to a possible solution (requires Dual Monitor support):
http://www.rdpslides.com/pptfaq/FAQ00231.htm
Here is the real solution (IMHO):
There is NO substitute (including hardware) for being prepared. All your
audience is going to see is you reading notes on your monitor! That won't
help your presentation at all.
Understand your materials, develop a concise presentation, practice your
delivery, get a remote mouse, and move around the room and WOW them with
your knowledge of PowerPoint and your topic! Another good trick to learn is
to know what materials are on your slides and how to move around if
necessary (F1 key in Slide Show Mode). For example, if someone asks about
something on Slide 30 and you are already on Slide 40, all you have to do is
to walk up to your keyboard, type "30" and press ENTER and you are back to
that previous slide. Once finished, type "40" and press ENTER and you are
back on track.