You can use masks to build a nearly endless list of effects in Flash. The default in this example movie is to show a highlight. By removing the background layer in this movie, you can change that effect to a spotlight. If you click on the mask, the masked image will enlarge slightly. This gives the effect of a magnifying glass. Just change the scale values to get a larger or smaller image. The mask will center itself under the cursor, move the cursor and the mask will move.
Some additional effects that you can easily employ:
You can download the original .fla file for this movie and use the contents if you like.