Creating such an application in perl would be fun, but if you are tied to powerpoint,
the simplest solution would be to annotate using...Powerpoint!
The app has simple text and drawing tools.
-Mark
Comment on Re: Scribble on PDF/PostScript: ghostpostscript.pm?
Yes, there is a simple drawing tool in ppt. One problem is that it does not run too well on Linux without purchasing a tool such as crossover office. I could perhaps use OpenOffice and try to import the slides, but I'd like something with more features. I thought that if I had (or created) perl source I could make a more flexible and open-source app.