Widget Manager

Downloading, installing, and removing Dashboard widgets has been greatly improved in Mac OS X 10.4.2 and later.

If you want to remove or disable widgets in Mac OS X 10.4.2 or later, meet Widget Manager! To access Widget Manager, simply do this:
In Dashboard, open the Widget Bar by clicking the plus sign ( ) button.
Click the Manage Widgets button on the left side of the screen, or click the Widgets widget in the Widget Bar.