Boilerplate for creating a simple Widget Plugin in Wordpress.

wp_widget_plugin.php

<?php
/*
Plugin Name: My Widget Plugin
Plugin URI: http://twitter.com/jamesbavington
Description: A simple plugin that adds a simple widget
Version: 0.1
Author: bavington
Author URI: http://twitter.com/jamesbavington
License: GPL2
*/

class wp_my_plugin extends WP_Widget {

  // constructor
	function wp_my_plugin() {
		/* ... */
	}

	// widget form creation
	function form($instance) {	
		/* ... */
	}

	// widget update
	function update($new_instance, $old_instance) {
		/* ... */
	}

	// widget display
	function widget($args, $instance) {
		extract( $args );
		echo $before_widget; // pre-widget code from theme
		/* ... */
		echo $after_widget; // post-widget code from theme
	}
}

// register widget
add_action('widgets_init', create_function('', 'return register_widget("wp_my_plugin");'));