Give your hardworking blog authors the credit they deserve. To insert an author box beneath a post insert this into your single.php after the article tags:

<div><?php echo get_avatar( get_the_author_email(), '80' ); ?></div> 
<div><?php the_author_meta( "display_name" ); ?></div> 
<div><?php the_author_meta( "user_description" ); ?></div> 
<div><?php if (get_the_author_url()) { ?><a href="<?php the_author_url(); ?>">Visit <?php the_author(); ?>'s website</a><?php } else { } ?></div> 

And here’s some CSS to make it pretty.

.author-box { padding: 10px; background: #ccc; border: 1px solid #333;} 
.author-left {float:left; width: 80px; margin:0 15px 0 0;} 
.author-right {float:left; font-size: 13px; margin:5px 0 0 10px;} 
.author-pic {border: 1px solid: #ccc;} 
.author-name {font-weight:bold;} 
.author-bio {padding:5px 0 5px 0;} 
.author-url {color: #555;} 
.author-url a {color: #000;} 
.author-url a:hover {color: #333;}
.clear {clear:both}