One of the problems with movies aliens is that they have a very limited range of emotional expression. It is this lack of subtle facial expressions that makes then unconvincing. The choice is wearing makeup and a mask or having animatronic figures are limited to the mechanics of the system. That might have changed. The method used at http://www.newscientisttech.com/article/dn10983-software-adds-surface-special-effects-with-a-click.html shows how various 'skins' can be added to a normal face to produce alien effects.
I've just come across an interesting site at http://digg.com/videos/animation/Filmmaking_fundamentals_explained_with_Animation
It is an animated movie about how to make Live-action movies. As I have never been a Live-action scriptwriter, I was surprised to find how many categories of shots and transitions there are in the medium.
My own training in scriptwriting was to simply sit in front of a film (this was in 1958 before TV) and mentally note the shots. It's advice I give to students as being quicker and cheaper than taking a course. Watching TV with the sound off will give much information on how the director is able to set up a scene.
Another interesting site is http://www.amathsdictionaryforkids.com/ which teaches basic mathematics using animation. Apart from being easy to use, it teaches the process of visualisation, which is a greatly underused ability.