Fritzing is an open source design tool for Bread Boards, Arduino's and lots of other hobbyist kits.
Its not only easy to learn but quite intuitive. It has both features of the Schematics Capture, Bread Board or Vero Board Design and PCB.
That makes it a complete tool for aspiring hobbyists like me too. Although I know to use Mentor Graphics Expedition(r) but that all for office for cheap and best you have FRITZING.
You can download the Latest updates at: http://fritzing.org/download/ .
Have a look at their Video:
You can also find the Tutorial Available: http://fritzing.org/learning/tutorials/ this is truly through and simple.
Many people have already developed their projects and have displayed on the site: http://fritzing.org/projects/
I have not finished any thing yet so I have not uploaded any. But the number of projects is growing at a rapid rate. There is an active Discussion forum supporting the development of this software and also help the people using it. http://fritzing.org/forum/
Hope that this project grows and some day many people even with the least know how on electronics and try out making innovative gadgets using this software.
Keep up the good work !!