I don't see where it can hurt. Whatever the eventual display size is, things can be adjusted as needed, and if it is displayed full screen, then you have a good fit for it and are not gambling it being stretched to fill, thus causing any bitmap content to possibly lose intended quality.
Would it make sense to make my Flash document the same dimensions?
His laptop resolution is not that important. You need to know the resolution of the projector.
Chances are it is 1024 x 768 or smaller. It could be hi def, but probably not. The resolution will also tell you the aspect ratio: standard 4:3 or hi def / wide 16:9. This is important so that you can design for maximum use of screen real estate.
thanks for the replys - im glad you said that meglamor!
so...if i find out the make and model (and then specs) of the projector itself, should i base my flash document dimensions on that?