If you ever wondered how to implement a shadowbox or thickbox in flash then look no further!
shadowbox --> http://mjijackson.com/shadowbox/
thickbox --> http://jquery.com/demo/thickbox/
Here are two examples
I did the shadowbox and someone else did the thickbox 
sorry i forgot source - if it is yours please let me know and I will acknowledge
From my experience on using both of them, i found that a shadowbox is a much better option.
Shadowbox uses javascript to hide the swf object when shadowbox is open - can display flash movies in shadowbox itself.
Thickbox relies on wmode = ‘transparent’ to show the thickbox on top of the flash - very crude solution which slows your framerate down alot and doesnt work in all browsers.
