Simon,
Sorry for the delay. Below is the PHP code you'll need to use to generate a link for the full-screen popup. You can use this anywhere you can put PHP code, and it will automatically fill out the necessary information to generate the URL:
$jfbcLibrary = JFBConnectFacebookLibrary::getInstance();
$configModel = $jfbcLibrary->getConfigModel();
$query = array();
$query['scope'] = $configModel->getRequiredPermissions();
$query['redirect_uri'] = 'http://YOUR-SITE.COM/index.php?option=com_jfbconnect&task=loginFacebookUser';
$query['client_id'] = $jfbcLibrary->facebookAppId;
$query = http_build_query($query, null, '&');
$loginUrl = 'https://www.facebook.com/dialog/oauth?'.$query;
echo '<a href="'.$loginUrl.'">Login!</a>';The main things that will be unique to your site are your Facebook Application ID and the "scope" (which are the permissions required). Additionally, the URL will be 'encoded' properly to make sure that all the parameters are passed to Facebook without issue.
Once you get that to generate the URL, you can actually copy the link itself creates anywhere and use it as raw HTML. It will be a long URL though, just so know.
Hope that helps, but if you run into any issues, or have questions, let us know!
Thanks,
Alex