GNU Cobol (formerly OpenCOBOL) is a free COBOL compiler. cobc translates COBOL to executable using intermediate C sources, providing full access to nearly all C libraries.
OpenCOBOL 1.1 continues on as GNU Cobol 1.1 Officially posted to ftp://ftp.gnu.org/gnu/gnucobol, also available here.
A superb manual by Gary Cutler, along with a FAQ / How-To, and other documentation is indexed at http://opencobol.add1tocobol.com/guides
As above, GNU Cobol is also authored by Simon Sobisch, Sergey Kashyrin, Joe Robbins, Ron Norman
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version.
The libcob run time support source tree is LGPL.