Adding this snippet to the functions.php of your wordpress theme will let you display a different icon for the wp-admin. Don't forget to upload your favicon.ico to the wp-content directory. Just a little snippet from great people over at wpengineer.com.
function favicon4admin() {
echo '<link rel="Shortcut Icon" type="image/x-icon" href="' . get_bloginfo('wpurl') . '/wp-content/favicon.ico" />';
}
add_action( 'admin_head', 'favicon4admin' );
what if it already does that? and you didn’t change anything? and there’s nothing like that in the functions?