Adding Categories to post-entry.php

Hi,

So I was recently able to resolve an issue regarding the flow of ‘elements’ on my site’s home page…only to run into yet another problem. The flow of my news is all well and good, but I’d really like to be able to display categories in a floating box to the left of the content, or even in a bar somewhere across the top. I am thinking this is more that not only will I have to edit the .php, but the .css file as well. So, my first problem is: what should I add to the .php?

<?php while (have_posts()) : the_post(); ?>
<div class="post">
<div class="postcontent">
<h2 class="entry-title"><a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></h2>
<?php the_content('Full Scoop...'); ?>
</div><!-- END Post Content -->
<div id="byline">
					Posted by <?php the_author() ?> On <?php the_time('F jS, Y') ?> / <?php comments_popup_link('No Comments', '1 Comment', '% Comments'); ?>
				</div><!-- /Post Byline -->
</div><!-- END Post -->
<?php endwhile; ?>

And my second problem is, how do I edit the .css in order to create a box or floating image to the top or left of the home page post?

My site is 8bitfoundation.com.

Any and all help is appreciated!