Background

jQuery Plugin: http://blog.jeremymartin.name/2008/02/building-your-first-jquery-plugin-that.html

http://mattberseth.com/blog/2008/07/jqueryui_progressbar_widget.html

http://docs.jquery.com/UI_Developer_Guide

http://bililite.com/blog/understanding-jquery-ui-widgets-a-tutorial/

http://bililite.com/blog/extending-jquery-ui-widgets/