List posts by category in Wordpress

<?php
//get all children of category "MyCat", then display posts in each cat
$taxonomy = 'category';
$param_type = 'category__in';
$cat_id = get_cat_ID('MyCat');
$term_args=array(
  'orderby' => 'name',
  'order' => 'ASC',
  'child_of' => $cat_id
);
$terms = get_terms($taxonomy,$term_args);
if ($terms) {
  foreach( $terms as $term ) {
    $args=array(
      "$param_type" => array($term->term_id),
      'post_type' => 'post',
      'post_status' => 'publish',
      'posts_per_page' => -1,
      'caller_get_posts'=> 1
      );
    $my_query = null;
    $my_query = new WP_Query($args);
    if( $my_query->have_posts() ) {
      echo '<ul>
        <li class="listheader"><h2>'.$term->name.'</h2></li>';
      while ($my_query->have_posts()) : $my_query->the_post(); ?>
        (my post content is here)
       <?php
      endwhile;
    } echo '</ul>';
  }
}
wp_reset_query();  // Restore global post data stomped by the_post().
?>