Gramps, the open source genealogy program
Gramps is a genealogy program for Linux, Windows, Mac, and FreeBSD that allows you to easily build and keep track of your family tree. It supports the GEDCOM standard, allows fine grained privacy controls and can generate many different types of reports (descendant trees, graphs, connection diagrams, ....)
PhpGedView is a revolutionary genealogy program which allows you to view and edit your genealogy on your website. It has full privacy functions, can import from GEDCOM files, and supports multimedia. It also simplifies family collaboration.
GenealogyJ is a viewer and editor for genealogic data, suitable for hobbyist, family historian and genealogy researcher. GenJ supports the Gedcom standard, is written in Java and offers many views like family tree, table, timeline, geography and more.