Security Links - 10/12/2007
EasyIDS - Installable IDS system based on CentOS. Includes a web GUI, snort, barnyard, ntop, etc.
SecureDVD - Bootable DVD containing 10 popular Security LiveCD distros. A bit dated as it still ships with BackTracks 1.0
SecurityDistro.com - Great site that lists and tracks security related Linux distros.
Nipper - Fantastic little open source tool for auditing configurations of many network devices. Similiar to the Cisco Router Auditing Tool (RAT), but supporting so many more devices, including Juniper/Netscreen Firewalls.
Ruby on Rails Security Cheatsheet - Great list of security best practices for Ruby on Rails.