This can be done using PowerShow at
http://officeone.mvps.org/powershow/powershow.html.

Look at the following links on how to set this up:

Synchronizing 2 or more shows:
http://officeone.mvps.org/powershow/powershow_sync_shows.html

See notes on 1 monitor and slide show on other:
http://officeone.mvps.org/powershow/tips_view_notes_slideshow.html

- Chirag

 Shortcut Manager - Assign keyboard shortcuts to menu items and macros
 http://officeone.mvps.org/ppsctmgr/ppsctmgr.html

I believe Chirag's PowerShow will do this nicely:

http://officeone.mvps.org/powershow/powershow.html

Otherwise, it is possible to do with only PowerPoint but it can be awkward.
Make sure PPT sees all of the displays in Slide Show/Set Up Show/Multiple
monitors.  If so, you're in business.  Make a copy of the presentation and
open.
The copy will be the "dummy" presentation that will show on the plasma.  
Which, by the way, you should be able to set at the plasma's native
resolution and format the dummy content to show correctly if you want it to
be full screen.  Now, in the main file, assign the slide show to the
projector.  In the dummy file assign the slide show to the plasma without
presenter view enabled.  You have to advance them seperatley using the
taskbar to activate each as needed.  I know this works because I've
demonstrated it.  I hope this process makes sense to you.  I've had a few
drinks tonight.  You should definitely check out Chirag's PowerShow too.

Good luck.......TD