The image that shows for the author comes from the email address set for that user which goes to a corresponding Gravatar. The display name and bio come from the User settings area in the Admin.
<div class="author-box"> <div class="author-pic"><?php echo get_avatar( get_the_author_email(), '80' ); ?></div> <div class="author-name"><?php the_author_meta( "display_name" ); ?></div> <div class="author-bio"><?php the_author_meta( "user_description" ); ?></div> </div>
That should be all the CSS hooks you need to style up the area however you want. Note: some of these functions are WordPress 2.8 and newer only.