Personal Ancestral File (PAF) is a free genealogy and family history program. PAF allows you to quickly and easily collect, organize and share your family history and genealogy information.
A download link
http://www.familysearch.org/Eng/Home/Welcome/simplePAFRegistration.asp you just have to enter your name and email address to download the software
I've used this tool quite a bit and it's very good for free software, you have the option to import/export .ged (GEDCOM) files, this is very useful as it seems to be the most widely used and recognised family tree file type.
