Preloader for external swf files


So i have this problem with the preloaders. See when you press a button two movies will load one will be a preloader the other will be the movie you want people to watch. The movies range fro 400K to 4 Mb. So anyway when I press the button I want the preloader and the movie to load. Since the preloader is small I want it to start playing as long as the other movie is loading.
Now Im loading both movies into seperate dumie movie clips.
thats about as detailed as it goes anyone got any ideas.