List all posts in 2 columns

How do you make a list of all your posts in 2 columns with the alphabetical letters? So far this code can only make 1 column

<?php
// Reference: http://wordpress.org/support/topic/148727

$posts = new WP_Query("cat=3&amp;orderby=title&amp;order=ASC&amp;showposts=-1");
if ($posts->have_posts()) :
	for($i='A';$i!='AA';$i++) :
?>
<h3 id="<?php echo $i; ?>"></a><?php echo $i; ?></h3>
	<ul>
<?php
		while ($posts->have_posts()) :
			$posts->the_post();
			if( $i == strtoupper(trim(substr($post->post_title, 0, 1))) ) :
?>
	<li><a href="<?php the_permalink(); ?>" rel="bookmark" title="<?php the_title_attribute(); ?>"><?php the_title(); ?></a></li>
<?php
			endif;
		endwhile;
?>
	</ul>
<?php
	endfor;
endif;
?>