Google has released SketchUp, a free 3D modelling application. In comparison to other software of the type, it's very easy to use. It'd be ideal for sketching out additions to your house (or a whole new one) or landscaping or designing or . . . well, whatever else comes to mind.
You can upload your images to the 3D Warehouse (from where I got the design at left) or import them into Google Earth.
It's only available for Windows now, but a Mac version is promised soon. Minimum requirements:
* Microsoft Windows - 2000, XP Home or Professional Editions
* 600 MHz Pentium� III processor
* 128 MB RAM
* 80 MB of available hard-disk space
* Video card that is 100% OpenGL compliant
* Windows compatible pointing device
* Microsoft� Internet Explorer 6.0 or higher
* Windows� Media Player or QuickTime 5.0 and web browser for multimedia tutorial.
You can download it here.