LEGO.com Digital Designer Virtual software is a free download. It is available for Mac and Windows platforms. The program allows users to build models using virtual LEGO bricks, in a computer-aided design like manner. This is a great free resource for Primary schools to use for design and technology. Zac has recorded a very short video demonstration for you:

In September 2012, I blogged the video below. You may like to use this video as in introduction to LEGO because it explains the origins of LEGO.