Circuit and Electronics Design and Simulators

• Quite Universal Circuit Simulator - http://qucs.sourceforge.net/
• FidoCadJ - http://freecode.com/projects/fidocadj
  • Arduino for FidoCADJ - http://www.grix.it/viewer.php?page=9520, Arduino + other librarys
• Fritzing - http://fritzing.org/home/
  • How to Create Practically Anything, Part 1: Fritzing Circuit Boards
  • How to Etch Your Own Circuit Boards Using a Laser Printer

Links

• http://forum.arduino.cc/index.php/topic,16945.0.html
• http://sourceforge.net/directory/science-engineering/eda/os:mac/freshness:recently-updated/