pcb2gcode is a command-line tool for isolation routing and drilling of PCBs that provides full support for both single- and double-sided boards. For more information, see http://sourceforge.net/apps/mediawiki/pcb2gcode/
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.