The KiCad software tool come with an additional component library package and a documentation package. Once you install all three packages you are set with a full fledged software tool for PCB design. Any necessary PDF documentation will be then available from the Help menu of each KiCad application (Eeschema, Cvpcb, etc.). The same documentation is available here too.
KiCad is an EDA software suite for the creation of professional schematics and printed circuit boards up to 32 copper layers with additional technical layers. KiCad runs on Windows, Linux and Apple OS X and is released under the open-source GNU GPL v2 free of charge.
If you like KiCad or are making a good living using KiCad in your toolset, you should consider donating funds used for development. CERN has put up a place to collect donations which will be used directly to support a developer.