Here's a dirty script I wrote to install nagios and Lilac on a clean CentOS 5.4 install. This script doesn't care about anyone other than itself (it'll change the mysql password for instance) so may not be entirely perfect for your needs.
Modular Object-Oriented Dynamic SpreadSheet (Moodss) is a graphical monitoring application with a complete graphical user interface (GUI) to conveniently monitor network services and send alerts when thresholds are crossed. Moodss is a deceptively simple tool that could characterized as a dynamic network-aware spreadsheet. It can poll devices using the Simple Network Management Protocol (SNMP), receive and send SNMP traps, and perform network service checks via Nagios plug-ins. It can optionally be used with the Modular Object-Oriented Multi-Purpose Service (Moomps) monitoring daemon to delegate monitoring tasks to a separate lightweight application after all thresholds have been defined with Moodss. The best way to see how Moodss operates is to walk through some examples so that’s what I’ll do in the steps below. I wish to give special thanks to Jean-Luc for his valuable assistance with Moodss on OS X, and for writing such a fine program.
Logdog is a tool that monitors messages passing through syslogd and takes action based on key words and phrases. Logdog has a configuration file which allows you to specify a list of key words or phrases to alert on, and a list of commands that can be run when those words are encountered. Logdog is licensed under the GPL.