Software

R is a very highly recommended open source (free) statistical analysis tool that runs on various operating systems. The website is www.r-project.org. The sources and binaries can be downloaded from cran.r-project.org/mirrors.html.
TeX Users Group is a great place to get started on TeX and LaTeX. The website is www.tug.org. Other great sources are the Comprehensive TeX Archive Network (CTAN) and the LaTeX Project.

Links to security-related software tools:

www.freefire.org/tools/

www.honeypots.net

www.insecure.org

www.astalavista.com

www.packetstormsecurity.org

www.freshmeat.net

www.net-security.org

www.securemac.com