How to add annoucements for authors

From my notes–add message to dashboard or admin panel:
http://wordpress.org/extend/plugins/pre-publish-reminders/
http://wordpress.org/extend/plugins/wp-cms-post-control/
http://wordpress.org/extend/plugins/wordpress-admin-notepad/

or a function

function my_admin_notice() {

  if(current_user_can('create_users')) {
    echo "
    <div id='my_admin_notice' class='updated fade'><p><strong>".__('This is meant for admins.')."</strong> ".sprintf(__('Hello admins.'))."</p></div>
       ";
  } else {

    echo "
    <div id='my_admin_notice' class='updated fade'><p><strong>".__('This is meant for non-admins.')."</strong> ".sprintf(__('Please call me to discuss your options.'))."</p></div>
       ";
  }
}
add_action('admin_notices', 'my_admin_notice');
return;