how to get a PHP variable to pass into Flash

I am using CS3 with AS3

When you click a button in the movie or on another link on a web page you are taken to a web page that requires a session ID in the URL. I also need flash to take that variable and use it in my switch statement.

Thanks

Read this, this, and this.

Also, SWFObject makes the process a bit simpler if you don't mind using Javascript.