Customize the Dashboard Logo
Add your own logo to the dashboard in the backend of WordPress to personalise your installation. This is a great tip for customizing client sites. Just paste the following code into functions.php:
add_action('admin_head', 'custom_logo');
function custom_logo() {
echo '
<style type="text/css"><!--
#header-logo { background-image: url('.get_bloginfo('template_directory').'/images/custom-logo.gif) !important; }
--></style>';
}