Controlling an SWF externally?

I just heard something about “Flash Methods”. Using Javascript to control the SWF from outside of it. Ever hear of it?

What I am trying to do is have the center content of my HTML page reload different textual content when you click on a button in the Nav, but not reload the whole page. The Nav is separate from the SWF content in the center of the page. Is there a way to have it so that when you click on one of the buttons in the Nav that it can tell the swf what fram to go to?

Please let me know if anyone knows how to do this. Sounds like it would be pretty simple if you know anything about how these “Flash Methods” work.