As a student teacher I am very interested in how effective "mini languages" such as Scratch, Logo, Alice and Lego mindstorms are in teaching the pupil the core concepts of programming such as variables, functions and loops.
Is one "mini language" better than another for teaching these basic core concepts?
Depending on how young the kids you are teaching are I would just go with a simpler language like python.
Here is a free book that teaches all the basics and is only about 200 pages long: http://www.greenteapress.com/thinkpython/thinkpython.html