[CS3,as2] how do parent and child communicate?

I know there’s a lot of these “help”'s going unanswered, but I’ll throw my line in the pond anyway.I’ve made a big pretty website. So big and so pretty that it takes more than two minutes to load. I figured I could make it smaller by breaking it up into separate swfs and loading them into a holder as required, but I have no idea how to make them talk to eachother. I’ll give a basic example.
So, i’ve loaded up my movie into the holder movie with:

loadMovie(“page1.swf”,“page1MC”);
and in page1.swf there is a button called “page1_buttonA”. In the old giant overweight site, onRelease it did a gotoAndPlay, but now I would like it to load the next part excitingly named page2.swf. For my own sanity’s sake I’d like to keep the most of the code controlling all the to-ing and fro-ing in the holder movie. So, what’s the format (syntax?) for getting the holder movie to notice what happens in the child movie and getting it to react accordingly? I hoped it was going to be as easy as:

//button that loads page 2
page1MC.page1_buttonA.onRelease = function() {
_root.createEmptyMovieClip(“page2MC”,2);
page2MC._x =0;
page2MC._y =0;

//Load movies into the page2MC movie clip:
loadMovie("page2.swf","page2MC");

}
but that doesn’t do anything. I’ve done a bit of digging, as I usually consider myself pretty good at reading help files and tutorials, but I’m at an awkward low-intermediate skill level where I skim read early stuff, but big blocks of code still make my eyes water. So, if anyone could help out, even if just to point out a useful tutorial for ‘how to build your really big flash website out of more useable little bits’, i’d be eternally greatful.

Also, I apologize that the title of this post sounds like it belongs in a childrearing forum. Being badly self-taught, my terminology is a little hazy.