LifeLines is a genealogy program to help with your family history research. Its primarily strengths are its powerful scripting language and the ability easily import and export information in the GEDCOM format.
Target is develop import and export filter for various data base systems from and to GEDCOM and GedXML (the XML specification of GEDCOM). The GEDCOM data format is prepared by "The Church of Jesus Christ of Latter-day Saints" (also known as Mormone)
gCensus is a Linux, GNOME-based program designed to be a program to store, index and sort Census data, for either genealogical or historical purposes. It will support as many Census formats as we can add into it.
OpenAncestry is a genealogical management tool written in C. It has a GTK+ interface, and has a database plugin architecture. Currently, OpenAncestry comes with a SQLite database plugin.
A callback GEDCOM parser for Ruby, including an interface for parsing standard GEDCOM formatted dates.
GENIO or GENalogical Information Organizer is and simple genealogical software to make it easy to organize the information of our ancestors.
Relativity is a free genealogical database program for Mac OS X.