This is the way I used the code for AREA203’s website, and it worked well.

<?php
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
query_posts("cat=4&paged=$paged&showposts=3");
if (have_posts()) : while (have_posts()) : the_post(); 
the_content();
?>
<?php endwhile; ?>
<div id="postNav">
<span class="previousNav"><?php previous_posts_link(); ?></span>
<span class="moreNav"><?php next_posts_link(); ?></span>
</div>
<?php else : ?>
<?php endif; ?>