I would start with Andrew's
Basic Training to learn the basis. Also, I would recommend you to have a look at Andrew's
DVD Products, I think
Serious FX could be a good start to learn effects and compositing.
Before you go on with Andrews stuff..i suggest you to buy Creating Motion Graphics Vol1 and Vol.2 from Thris and Chris Meyer.
These
books will give you the basic principles of the programm and also make
you feel comfortable with the interface of the programm such as its
basic rules and knowledge.
You must know how to put the gears in
order to drive a car.....Andrews stuff is surely your next stop after
you manage to drive you A.E vehicle goood!!