Unfortunately, this online tool is no longer available. If you try to access it, you’ll be redirected to Autodesk’s new online CAD program called TinkerCAD, which is a great free CAD software btw.
If anybody is looking for a good (and free) breadboard simulator, i can recommend the one from Autodesk: 123D Circuits
You can simulate the most important electronic components, some µcs and even program arduinos and simulate their behaviour with your circuits.
Beside these great features you can share your electronic experiments with others in the community and look at their circuits. It’s also possible to print your breadboard to rebuild it in real life easily. When you finished your breadboard experiment, a pcb can be designed and ordered online (you get it cheaper this way than regularly). After ordering the pcb you can also create a list with the necessary parts and order them online too.
And the best thing is: It’s free!