KiCad is an Open Source EDA package (Electronic Design Automation). More information on it’s features can be found at this link : http://kicad-pcb.org/about/kicad/
It is available for all platforms - Linux, Mac, Windows and can be downloaded from this link : http://kicad-pcb.org/download/
For any queries related to KiCad, first search the Software Categories to check if it has already been answered. If not, please create a new topic with a descriptive heading.
A lot of useful resources are available from the HELP section on the KiCad website : http://kicad-pcb.org/help/getting-started/