Adding a preloader to an already existing Flash movie

I created a Flash movie that takes some time to upload (even with DSL) and wanted to add a preloader to it. Can this be done after the fact? If so, how? I’ve read: http://www.kirupa.com/developer/mx/percentagepreloader.htm and understand how to create the preloader, just not sure how to connect it to my already existing Flash movie. And would anything need to change in the action script?

Hal