indispensible, works great once you realize that the "button with a red circle" is the add layer mask button at the bottom of the layers palette, and that to select all non-transparent pixels you need to control-click on the layer IN THE LAYERS PALETTE, not in the layer itself.
use of nest for effects, including widescreen; how to apply to a nested sequence so you don't have to do it to each clip individually
finally, a good tutorial on getting nice ease in & out motion on still zooms & pans