TinkerTool
TinkerTool is an application that gives you access to additional preference settings Apple has built into Mac OS X. This allows to activate hidden features in the operating system and in some of the applications delivered with the system.

PrefEdit
PrefEdit is a utility that allows you to inspect and edit all preference settings for Mac OS X applications. The settings are displayed in a browser and can be edited by simple point-and-click operations. You can also do a full-text search on all settings, or clean up unused entries of applications that have been uninstalled

Widget Manager
Widget Manager is a Preference Pane for OSX 10.4 that allows you to inspect, remove, and disable Dashboard Widgets. Widget Manager is a convenient way to manage all the Widgets on your system, including the standard Apple Widgets.