Random help question

Ok, so I have seen this effect on several sites now but this is the only one i can find an example for. I think I even found a tutorial on how to do it once but I have no idea where it went.

http://www.passion-pictures.com/flash.html#page=d15

How can I create that effect? I have thumbnails and when they are clicked on, I want the image to appear in a flash popup that needs to be clicked to be closed and the background is dimmed out.

Any idea on where I can find a tutorial to do this sort of thing?

Thanks