Deprecated - Use https://gist.github.com/jandro935/0d4cddf243e13b91550f instead

u87.php

// Widget Base Code
add_action("widgets_init", array('Widget_name', 'register'));

class Widget_name {
	function control(){
		echo 'I am a control panel';
	}
	function widget($args){
		echo $args['before_widget'];

		// Widget Content ...

		echo $args['after_widget'];
	}
	function register(){
		register_sidebar_widget('Widget Name', array('Widget_name', 'widget'));
		register_widget_control('Widget Name', array('Widget_name', 'control'));
	}
}