Fancybox plugin: triggering on href attribute

jQuery('a[href^="http://www.everytrail.com/view_trip.php?trip_id=2027383"]').fancybox({

Try this.

<script type="text/javascript">

jQuery(document).ready(function($) {
     jQuery('a[href="http://www.everytrail.com/view_trip.php?trip_id=2027383"]').fancybox({
'transitionIn': 'elastic', 'transitionOut': 'elastic', 'speedIn': 600, 'speedOut': 200, 'type': 'iframe', 'height': 800 });
    });

</script>

I checked on my DEMO, and it works for me

Make sure your site already load jQuery : if there is no jquery.js loaded, use the following code to load

<?php wp_enqueue_script('jquery');?>

add the above code before <?php wp_head(); ?> in header.php //