Put the links in a <ul>
(Unordered list element) with style of float:left
like so
<body>
<ul>
<?php
foreach ($feed->get_items() as $item):?>
<li class="item"><a href="<?php echo $item->get_permalink(); ?>"><?php echo $item- >get_title(); ?></a>
</li>
<?php endforeach; ?>
</ul>
</body>