One sidebar per category

Hi,

I often find myself in need of custom widgets or boxes of some sort for displaying related information on a per post/page basis.

Specifically, I’m trying to create a sidebar per category for displaying widgets with related content for each category in my category archive.

I have tried the following in functions.php but it doesn’t seem to work. However, I can’t figure out why it doesn’t. Does anyone have any ideas?

<?php
  $categories = get_categories('orderby=name&order=asc');
  foreach ($categories as $category) {
    register_sidebar(array(
      'name' => $category->category_name,
      'id' => $category->category_nicename,
      'before_widget' => '<div id="%1$s" class="%2$s widget">',
      'after_widget' => '</div>',
      'before_title' => '<h3 class="widget-title">',
      'after_title' => '</h3>'
    ));
  }
?>

Any help is much appreciated.