gmap marker popup via AHAH code

marker-popup_code.php

<?php 

// following is excerpted from um_common.module: 

// service area vid
define("SERVICE_AREA_VID", 32);

/**
 * Implements hook_menu()
 * Creates Gmap rendering callbacks for popups.
*/
function um_common_menu() {
    // marker popup callback
    $items['gmap-popup/%node'] = array(
      'page callback' => 'um_common_node_popup_render',
      'page arguments' => array(1),
      'access callback' => 'gmap_node_map_access',
      'access arguments' => array(1),
      'weight' => 2,
      'type' => MENU_CALLBACK
    ); 
	
  return $items;
}

/* Page callback for single marker popup */
function um_common_node_popup_render(&$node) {
  print theme("node_marker_popup", $node);
}

function um_common_theme() {
  return array(
  // call using theme('node_marker_popup', $node)
	
  // provides templated theming function to um_common_node_popup_render()
  'node_marker_popup' => array(
      'template' => 'node-marker-popup',
      'arguments' => array(
        'node' => null,
      ),
   ),
    
    /* adds preprocess to set up variables for the marker popup */
    'preprocess_method' => array(
      'template' => 'node_marker_popup',
      'arguments' => array('node' => null),
    ), 
  );
}

/* Preprocess for node_marker_popup */
function um_common_preprocess_node_marker_popup(&$vars) {

  if(isset($vars['node']->location)) {
    $vars['address'] = theme('location', $vars['node']->location); 
  }

  switch($vars['node']->type) {
    case 'volunteer_opportunity':
      $title_text = 'Volunteer in ' . $vars['node']->title;

      if(isset($vars['node']->taxonomy) && is_array($vars['node']->taxonomy)) {
        foreach($vars['node']->taxonomy as $term) {
          if ($term->vid == SERVICE_AREA_VID) {
            $terms[] = array('href' => 'taxonomy/term/' . $term->tid, 'title' => $term->name);
          }
        }
        $vars['service_areas'] = theme('links', $terms, array('class' => 'links', 'style' => 'display: inline;'));
      }

      if(isset($vars['node']->field_volopp_org_name[0]['value'])) {
        $vars['organization_name'] = $vars['node']->field_volopp_org_name[0]['value']; 
      }
      break;

      default: 
        $title_text = $vars['node']->title;
        $node_title = $vars['node']->title;
      }

    $vars['node_link'] = l($vars['node']->title, $vars['node']->nid, array('attributes' => array('class' => 'opp-title', 'title' => 'Volunteer in ' . $node_title)));
}

?>

<?php and in node-marker-popup.tpl.php (same directory as module) ?>

<?php
// $Id

/**
 * @file node-marker-popup.tpl.php
 *
 * Theme implementation to display a marker popup.
 * Different variables are available based on node type.
 *
 * Available variables:
 * - $node_link: the node title, linked to the node.
 * - $address: the address, if there is one.
 * For volunteer opportunities only:
 * - $organization_name: the name of the organization
 * - $service_areas: the terms from the service areas taxonomy, as links
 *
 * @see um_common_preprocess_node_marker_popup()
 */
?>

<?php if($node_link) { print $node_link; } ?>
<br />
<?php if($organization_name) { ?>
<strong>Organization:</strong> <?php print $organization_name; ?>
<br />
<?php } ?>
<?php if($service_areas) { ?>
<strong>Service Area:</strong> <?php print $service_areas; ?>
<br />
<?php } ?>
<?php if($address) { ?>
<strong>Address:</strong> <?php print $address; ?>
<br />
<?php } ?>