A CakePHP helper that displays navigation dynamically. It detects what page you're in and adds a class "active" to the list element.

display.php

<?php
class DisplayHelper extends AppHelper {

    var $helpers = array('Html');

    /**
    *
    * Display navigation and detects currect page and adds 'active' class
    * to the <li> tag
    *
    */
    function navigation() {
        $nav = array(
                'Home' => '/',
                'About' => 'about',
                'Login' => 'users/login',
                'Sign up' => 'users/signup'
            );
        $url_string = $this->params['url']['url'];
        $output = '<ul>';

        foreach($nav as $label => $url) {
            $li_class = '';
            if(($url == $url_string) || ((false !== strpos($url_string, $url) && $url != '/'))) {
                $li_class = ' class="active"';
            }
            $output .= '<li' . $li_class . '>' . $this->Html->link($label, '/'.$url) . '</li>';
        }
        $output .= '</ul>';
        
        return $output;
    }
}
?>