Scratch is a visual programming environment that allows students to easily learn the constructs of computer programming that the environment provides. It comes with an extensive library of programs that can be deconstructed to allow the relatively rapid uptake of a basic understanding of programming.

To download the program (which is free) and the resources, go to http://scratch.mit.edu/

Here is a fabulous video showing how easy it is to create with Scratch.
Here is a similar and shorter video with voice over showing how to create a square.

This is a primary oriented link to Scratch learning resources. There are a lot of videos etc here.

A basic course on programming in Scratch by Mike Leishman in WA.