How to Create Your Own Widget on the Mac Dashboard
You’re not limited to the widgets provided by Apple on the Mac Dashboard, or the widgets you find available as freeware or for a fee. You can select a portion of a Web page and create a widget that shows the latest version of just that piece, a feature Apple calls WebClips. To create your own widget on the Mac Dashboard, open Safari and go to the Web site you want to turn into a widget. Choose File→Open in Dashboard or click the Dashboard icon. Select the section of the page that you want to capture.
Apple even provides a program, called Dashcode, to help you build your own widget. You can even create a widget to track your favorite blog. The possibilities are endless. Dashcode is in the Xcode folder on your OS X install DVD.
You can even use Apple’s Widget widget to manage all your widgets.