Using Flash With PowerPoint 97/2000

I am setting up a presentation to be viewed via overhead projector on a large screen. i would like to incorporate an extensive flash movie with photos and transitions in the beginning of the powerpoint presentation utlizing flash. I am not sure what size to make the stage and contents of the movie in flash before bringing it in Powerpoint. Is there a specific dimention to go by? Also after inserting an extensive flash movie in powerpoint could it become unstable? Can PowerPoint handle it? Thanks, i am very new to this, any help would be appreciated.