gramps-project.org
GRAMPS helps you track your family tree. It allows you to store, edit, and research genealogical data. GRAMPS attempts to provide all of the common capabilities of other genealogical programs, but, more importantly, to provide an additional capability of integration not common to these programs. This is the ability to input any bits and pieces of information directly into GRAMPS and rearrange/manipulate any/all data events in the entire data base (in any order or sequence) to assist the user in doing research, analysis and correlation with the potential of filling relationship gaps.
GRAMPS currently runs on Linux, BSD, and Solaris -
and Apple OS X. For more information about getting GRAMPS, see the download page."
operating systems.