/*** Implements hook_menu ***/
    function ea_custom_menu() {
      $items['users/%user'] = array( //the %user will be used as argument for the page callback
        'title' => t('User Profile'),
        'page callback' => 'ea_custom_render_userpage',
        'page arguments' => array(1), //zero base array. This tells hook menu to first load user with the specified uid specified by %user parameter.
        'access callback' => 'user_access', //so non-onwer can also view it
        'access arguments' => array('access content'),
      );
      return $items;
    }

    /**** page callback for users/%user ****/
    function ea_custom_render_userpage($user) {
       //you now have accessed to the user object
       drupal_set_message('<pre>' . print_r($user, TRUE) . '</pre>');

       //assemble your output using the values inside $user object
       $output = $user->uid; //etc.. etc...

       return $output;
    }