odd placement on my sidebar widget

so i have begun to join the world of widget programming and have run really only into this problem.
If you visit http://ponymouse.com you will see the authors listed in the top left of the screen, that is one of my sidebar widgets activated. I want that to be displayed in my sidebar. here is my code, I cant figure out why my code isnt working.

add_action('widgets_init', 'widget_display_author_init');
function widget_display_author_init() {
  	if ( !function_exists('register_sidebar_widget') ) {
  		return;
	}
  	function widget_display_author($args) {
  		extract($args);
  		echo "$before_widget<div id='display_author'></div>$after_widget";
	}
  	register_sidebar_widget('Display Author', 'widget_display_author');
}

add_action('wp_head', 'display_author_wp_head');
function display_author_wp_head() {

	echo wp_list_authors($optioncount = 'true');
}