<?php query_posts('post_type=slashies&posts_per_page=3'); ?>
<?php $count = 0; ?>

<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
<?php
$extra_class = "";
if($count % 3 == 0){
$extra_class = "alpha";
}elseif($count % 3 == 2){
$extra_class = "omega";
}
?>
<div class="grid_3 partner <?php echo $extra_class ?>">
	<?php if ( has_post_thumbnail()) the_post_thumbnail('220-square'); ?>
	<h3><?php the_title();?></h3>
	<?php the_content(); ?>
	<?php if ( get_post_meta($post->ID, 'partner-website', true) ) : ?>
	<p></p><a href="<?php echo get_post_meta($post->ID, 'partner-website', true) ?>" title="<?php the_title();?>" target="_blank" rel="bookmark">Visit Partner Website</a></p>
	<?php endif; ?><!-- end link check -->
</div>
<?php $count++ ?>
<?php endwhile; else: ?>
	<p><?php _e('Sorry, no posts matched your criteria.'); ?></p>
<?php endif; ?>
<?php wp_reset_query(); ?>

Used this on the vox site to find a custom post type and then assign a variable to get different classes for the output.

Wordpress Get Custom Post Type and Count posts for CSS Classes

wordpress

PHP