Load more posts

Hi there,

I have bitten off more than i can chew regarding a website request from a client.

They are wanting to have a ‘Load More’ button at the bottom of a row of 3 posts.

When the ‘View More’ button is clicked it loads another row of 3 posts.

I have the code currently pulling in the posts. Beyond that, I am stumped. Can someone point me in the right direction?

<div id="posts-bottom">
<ul>
<?php $cat_name = 'Secondary';?>
<?php query_posts('category_name='.$cat_name); ?>
<?php while (have_posts()) : the_post(); ?>                

<li>
<div id="posts-bottomitem" align="center">
<a href="<?php the_permalink(); ?>"><?php echo get_the_post_thumbnail( $post_id, $size, $attr ); ?></a>
<a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
<p><?php $content = get_the_content();
$content = strip_tags($content);
echo substr($content, 0, 150); ?></p>
</div>
</li>

<?php endwhile;?>
</ul>
</div>

<div id="break"><div id="viewmore">View More</div></div>

Thank you for any help,

P