A command line tool that allows you to (live) analyze netfilter (iptables) log files. It provides a nice output and has features like displaying hostnames, duplicate detection... More info (+ screenshots) can be found in the pdf inside the tarball.
A network monitor for the GNOME desktop. Includes overview of processes communicating on the network (similar to top for cpu load), network interface statistics, network statistics overview and iptables loganalyzer.