gEDA: geda.seul.org

Ngspice Project: www.sf.net/projects/ngspice

Gnucap: the Gnu Circuit Analysis Package: geda.seul.org/tools/gnucap/index.html

Icarus Verilog: www.icarus.com/eda/verilog

“Icarus Verilog: Open-Source Verilog More Than a Year Later” by Stephen Williams and Michael Baxter: /article/6001

PCB, an Interactive Printed Circuit Board Editor: pcb.sf.net

Circuit Simulation Using SPICE on gEDA HOWTO: www.brorson.com/gEDA/HOWTO

Footprints Collection for gEDA: www.luciani.org/geda/pcb/pcb-footprint-list.html

A large collection of open-source applications is listed at www.opencollector.org