WordPress: Custom widget

messenger.php

<?php
/*
Plugin Name: Messenger Widget
Plugin URI: http://vienhoang.com
Description: Display any messages.
Version: 1.0
Author: Vien Hoang
Author URI: http://vienhoang.com
License: GPL2
*/

class Messenger extends WP_Widget {

	public function __construct() {
		// Description and name for the widget on dashboard
		$params = array(
			'description' 	=> 'Display messages to readers',
			'name' 			=> 'Messenger'
		);

		parent::__construct( 'Messenger', '', $params );
	}

	public function form( $instance ) {
		extract( $instance );
		?>

		<p>
			<label for="<?php echo $this->get_field_id( 'title' );?>">Title: </label>
			<input 
				class="widefat" 
				id="<?php echo $this->get_field_id( 'title' );?>"
				name="<?php echo $this->get_field_name( 'title' );?>"
				value="<?php if ( isset( $title ) ) echo esc_attr( $title );?>"
			/>
		</p>

		<p>
			<label for="<?php echo $this->get_field_id( 'description' );?>">Description: </label>
			<textarea 
				class="widefat" 
				id="<?php echo $this->get_field_id( 'description' );?>"
				rows="5"
				name="<?php echo $this->get_field_name( 'description' );?>"><?php if ( isset( $description ) ) echo esc_attr( $description );?>
			</textarea>
		</p>
	<?php
	}

	// Method for responsible for displaying 
	public function widget( $args, $instance ) {
		extract( $args );
		extract( $instance );

		$title = apply_filters( 'widget_title', $title );
		$description = apply_filters( 'widget_description', $description );

		echo $before_widget;
			echo $before_title . $title . $after_title;
			echo "<p>{$description}</p>";
		echo $after_widget;

	}
}

add_action( 'widgets_init', 'vh_register_messenger' );

function vh_register_messenger() {
	register_widget('Messenger');
}