Newb Question about preloaders

So im barely 9 months into flash 8, but im in love and have already created over 200 swfs.

I m struggling huge on preloaders. Ive done like 15 tutorials and they never come out right. I just want a preloader that i can make once and reuse it for everything in my site.

I dont get the concept i guess. Any suggestions on how to test your preloader, I have a local webserver so its hard to test and see the thing.

Also, if I did create just one preloader i wanted to use over and over, can i copy the preloader into a large fla, and where? In the first frame of a large fla.

I would be even willing to download a source preloader from here and test it on my own files, if anyone had a hint on to where to begin that project.

Anyone?

You can set up your previews to reflect certain bandwidth speeds. Ctrl+enter to view your movie, then ctrl+enter again to view with whatever bandwidth you have it set to. Someone in the settings on the preview window is a section where you can set the preview speed to like 14.4kb/s, 28.8kb/s, etc.

I use the same preloader in all my movies, i just change the graphics on it. I have my preloader in scene one and then whatever site work im doing in scene 2. Makes it nice to keep the preloader seperate.