Current page

I want to create an extra button on my header navbar. Only for registered users. Getting it there isn’t a problem, but get the javascript working that tab opened is marked. This is what I’m useing right now but it doesn’t works! (It looks like is_page doesn’t return anything?)

<div id="navigation" class="menu clearfix">
		<ul class="lavaLampWithImage">
			<li class="page_item <?php if(is_home()): ?>current_page_item<?php endif ?>">
            <a href="<?php echo get_option('home'); ?>/">Home</a>
            </li>

			<?php wp_list_pages('sort_column=menu_order&depth=1&title_li=');?>

<?php

	if ( is_user_logged_in() ) { ?>
<li class="page_item <? if(is_page('52')): ?>current_page_item <? endif ?> ">
            <a href="index.php?p=52">PM</a>
	 </li>
<? } else {	}; ?>

My website is at:
http://bruteforces.clanservers.com/

I hope someone could help me a hand =)