Is there something usefull around?
Lightbox like functionality in Flash is very basic and native to it. It is as simple as creating a displayobject, putting images on its display list and creating some transition effect with tween engine. But this requires knowledge of ActionScript.
You can also do this these things on timeline manually.
Because it is so basic, you, perhaps will not find any tutorials. Even beginner's level of Flash skills enables one to develop this kind of functionality.