Freeware Programs: Anders Isaksson
BlockCAD v1.8 allows you to use Lego-like blocks to build whatever you can imagine. You can use a variety of blocks which you can easily color.
AnkerCAD 1.3 With AnkerCAD you can save your models, or save pictures of them (.bmp, .jpg), even reuse a complete model as a part in another model. Everything can be controlled with the mouse, but it's also possible to use the keyboard for most of the commands,