Drupal - Collapsible Form Item Descriptions

Original Credit to Drewish, and of course the CCK team for such a fantastic tool. I'm just adding it here for reference, and expanding a bit with the uninstall knowledge.

Install

// Need to load the CCK include file where content_field_instance_create() is defined.
module_load_include('inc', 'content', 'includes/content.crud');

// If you wanted to add the field to several node types, loop over them...
foreach (array('athlete', 'feature', 'product', 'tech') as $type) {
  // ...and assign the node type.
  $field['type_name'] = $type;
  content_field_instance_create($field);
}
// Need to load the CCK include file where content_field_instance_create() is defined.
module_load_include('inc', 'content', 'includes/content.crud');

// If you wanted to add the field to several node types, loop over them...
foreach (array('athlete', 'feature', 'product', 'tech') as $type) {
  // ...and assign the node type.
  $field['type_name'] = $type;
  content_field_instance_create($field);
}

Uninstall

content_field_instance_delete($field_name, $content_type);
content_field_instance_delete($field_name, $content_type);

Note that removing the last instance of a field will remove the field's definition from the database. So you're clean just doing this.