All available variables returning node ID in views php in drupal 7
Start with print_r to see what's available:

&lt;pre&gt;
&lt;?php print_r($data); ?&gt;
&lt;/pre&gt;


You will likely end up using $data, something like:

$data-&gt;_field_data['nid']['entity']-&gt;field_facebook_page['und'][0]['value']


If that doesn't work, take a look at 
http://drupal.org/node/1140896#comment-5945164