Immediately below the title tags:

<h2><a href="<?php the_permalink() ?>" title="<?php the_title(); ?>"><?php the_title() ?></a></h2>

Add the following:

<p class="articleAuthor">By: <?php the_author(); ?></p>

Tweak the look in the stylesheet using the class .articleAuthor {}. More information concerning the_author() can be found in the WordPress Codex.

For Grid Focus users, here is a quick way to integrate the 468 x 60 AdSense image / text banner ad.

<div class=”adsenseBanner”>
<!– your adsense code –>
</div>

1. Create a new template file – for this example I’ve created adsense.php and pasted the code below + your unique AdSense script.

.adsenseBanner {
float: left;
margin: 30px 0 5px 50px;
}

2. Add the following CSS to style.css.

<?php include (TEMPLATEPATH . ‘/adsense.php’); ?>
<?php include (TEMPLATEPATH . ‘/second.column.post.php’); ?>
<?php include (TEMPLATEPATH . ‘/third.column.shared.php’); ?>

3. Reference the template file in index.php, single.php, and page.php above the calls for the second and third columns.