Add a page template column to WordPress's Pages view.

page_template_column.php

<?php 

/**
 *
 * Add page template column to page listing. Make the Template column sortable
 * http://www.codehooligans.com/2011/07/13/adding-custom-columns-to-wordpress-post-listing/
 * http://justintadlock.com/archives/2011/06/27/custom-columns-for-custom-post-types/
 *
 */

add_filter( 'manage_edit-page_columns', 'admin_page_header_columns', 10, 1);
add_action( 'manage_pages_custom_column', 'admin_page_data_row', 10, 2);
add_filter( 'manage_edit-page_sortable_columns', 'my_page_sortable_columns' );
add_action( 'load-edit.php', 'my_edit_page_load' );

function admin_page_header_columns($columns) {
 if (!isset($columns['template']))
  $columns['template'] = "Template";
 
 return $columns;
}

function admin_page_data_row($column_name, $post_id) {
 switch($column_name) {
  case 'template':
   global $post;
   $template_file = get_post_meta( $post_id, '_wp_page_template', TRUE );
   echo $template_file;
   
   break;
      
  default:
   break;
 }
}

function my_page_sortable_columns( $columns ) {
 $columns['template'] = 'template';
 return $columns;
}
function my_edit_page_load() {
 add_filter( 'request', 'my_sort_pages' );
}
function my_sort_pages( $vars ) {
 if ( isset( $vars['post_type'] ) && 'page' == $vars['post_type'] ) {

  if ( isset( $vars['orderby'] ) && 'template' == $vars['orderby'] ) {

   $vars = array_merge(
    $vars,
    array(
     'meta_key' => '_wp_page_template',
     'orderby' => 'meta_value'
    )
   );
  }
 }
 return $vars;
}