David Josephsen recently published this book which contains best practices for building monitoring infrastructure, lessons in operational theory focused on the usage of Nagios, and practical guidance for implementing Nagios. David wrote the book in a way primarily useful for system engineers and enterprise architects, though it has information relevant to most roles in technology.
This book is written by Brendan Gregg and Jim Mauro, both expert users in DTrace and the Solaris Internals from Prentice Hall. It covers the key features of the DTrace environment, the D language that is used to write the scripts used to provide answers to questions regarding the performance of the system under question.
Scout is an extensible server and application monitoring service which focuses upon ease of installation and configuration.
A introduction to creating Flash charts using the FusionCharts Free from Ruby, complete with a feature comparison of other charting libraries. 8