We're working on a 'quick' development guide that may help you to do this. There's no script already made for it, but something like the below should work if you're up for putting it in your site.
require_once (JPATH_ROOT.DS.'components'.DS.'com_jfbconnect'.DS.'helpers'.DS.'facebookhelper.php');
$fbClient = JFBConnectFacebookHelper::getFbClient();
if ($fbClient->user != null)
{
<a href="http://www.facebook.com/">GO TO FACEBOOK</a>
}
This isn't tested, but let us know how it goes and we should be able to help.