/*
Copyright (c) 2008, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.net/yui/license.txt
version: 3.0.0pr2
*/
/**
 * Percents could work for IE, but for backCompat purposes, we are using keywords.
 * x-small is for IE6/7 quirks mode.
 */
body {
	font:13px/1.231 arial,helvetica,clean,sans-serif;
	*font-size:small; /* for IE */
	*font:x-small; /* for IE in quirks mode */
}

/**
 * Nudge down to get to 13px equivalent for these form elements
 */ 
select,
input,
button,
textarea {
	font:99% arial,helvetica,clean,sans-serif;
}

/**
 * To help tables remember to inherit
 */
table {
	font-size:inherit;
	font:100%;
}

/**
 * Bump up IE to get to 13px equivalent for these fixed-width elements
 */
pre,
code,
kbd,
samp,
tt {
	font-family:monospace;
	*font-size:108%;
	line-height:100%;
}

<?php
function get_author_bio ($content=''){
    global $post;

    $post_author_name=get_the_author_meta("display_name");
    $post_author_description=get_the_author_meta("description");
    $html="<div class='clearfix' id='about_author'>\n";
    $html.="<img width='80' height='80' class='avatar' src='http://www.gravatar.com/avatar.php?gravatar_id=".md5(get_the_author_meta('user_email'))."&default=".urlencode($GLOBALS["defaultgravatar"])."&s=80&r=PG' alt='PG'/>\n";
    $html.="<h4>Author: <span>".$post_author_name."</span></h4>\n";
    $html.= $post_author_description."\n";
    $html.="</div>\n";
    $html.="<div class='clear'></div>\n";
    $content .= $html;

    return $content;
}

add_filter('the_content', 'get_author_bio');
?>