Software giant AutoDesk took a big plunge into the 3D consumer space by releasing 123D Design, a very user-friendly 3D modeling tool. The software is available for iPad, Mac or PC and also directly on the web if you don't have any of those platforms.
We took 123D Design for a spin and found that indeed it is extremely friendly. Menus and controls are simplified, yet still seem to provide more than sufficient power for the typical consumer. No, this won't replace your SolidWorks or other commercial tools by a long shot, but for some people this may be just what they need. It may even be suitable as an introduction to 3D modeling for those who have never attempted it.
There is a but, and a big one. The tool does not seem to have a way to export STL. You may save your design in 123D format either on your device or in the cloud. If you want to 3D print your design you are only permitted to choose one of several 3D print services: Shapeways, i.Materialise or Sculpteo. If you wish to use those services, terrific. But if you have your own 3D printer or want to use any other service, 123D Design is not for you.