My idea of it to work was based on how you upload your logo images now. In admin you choose upload a advert, you choose if you want the advert before or after the video (or both) then it asks you to select 'Preroll Advert.flv' and then 'Postroll Advert.flv' you then click upload and the server converts it as if it is a video. Then in admin it has a spot like it already does for banners, allowing you to activate and deactivate it.
Would be nice, and as i said earlier i gave these ideas and my demo to the admin which he is looking into so it may be a release in the near future fingers crossed.