Need External Preloader Tut

I have a main swf and 5 buttons, i attached to each button a loadMovie action so that an external swf, or jpg loads into a specified empty movie clip.
now i realized that the movie takes time until it's loaded and there is not response given to the user, until the external swf is loaded. so i decided to create an external preload bar that works globally to preload the external movies into the empty movie clip.
the preloader should be general in order not to create a bar for each button.
I have been looking for a tute but all tutorials are very complicated and they arent much helpful, and i cant find a solution it them.

Is there any simple tutorial to do that?

Regards