= kicad =
KiCad is an EDA software suite for the creation of professional schematics and printed circuit boards up to 16 layers. KiCad runs on Windows, Linux and Apple OS X and is released under the open-source GNU GPL v2 free of charge.

http://www.kicad-pcb.org/display/KICAD/KiCad+EDA+Software+Suite

Software tools:
 * eeschema, schematic editor.
 * pcbnew, printed circuit board editor. 
 * gerbview, GERBER file viewer.
 * cvpcb, footprint selector for components association.