Preloader and loading external .swf

I am sure that probably a thousand people have posted this and asked this question but how do you make a preloader. I used one that someone posted a tutorial thing on and it has stopped working for some reason. The preloader doesn’t work on any of my new flash stuff and I think it is becuase I have Flash MX 2004 now and I didn’t used to.

And I also am wondering about how to load external .swf into a flash file. I know that lots of people have asked about this as well. So if anyone can help me or maybe post a link to one of such tutorials or just tell me how to do it I would be very thankful.