Lire is a pluggable log analyzer, supporting HTTP, email, DNS, FTP, firewall and print services. Output generated can be txt, (X)HTML, PDF, RTF, and DocBook. The latter four support graphics. For news/support visit the project homepage.
Nmap Log Stripper is a Bash script intended to be a way to condense all, or some, of the IPs of a "random" (-iR) nmap scan into a file for later usage.
RJStats assists in network and host monitoring by creating many graphs of your servers using rrdtool. These graphs can be viewed using a web browser in any combination you would like to see them.
Green Screen: A Linux based Advanced Syslog Server for Juniper NetScreen Firewalls - Can be expanded later to support other products. It can capture syslog messages, parse them, store them in a MySQL database. A Web GUI interface is also included.
Shoki is a free, open source network intrusion detection system. The fundamental design goals are simplicity and modularity, and the focus is on traffic analysis rather than content inspection.