Add “Featured Posts” to your Thematic child theme

function featured_posts(){
 
		$my_query = new WP_Query('tag=featured&showposts=3');
 
		echo '<ul id="featured-posts">';
		$feat_class = array();
 
		while ($my_query->have_posts()) : $my_query->the_post();
				$feat_class = array();
				// Category for the post queried
				foreach ( (array) get_the_category() as $cat )
					$feat_class[] = 'category-' . $cat->slug;
					$feat_class = join(" ", $feat_class);
				?>
				<li id="featured-<?php the_ID(); ?>" class="<?php echo $feat_class; ?>">
					<?php 
						$posttitle = '<h4><a href="';
						$posttitle .= get_permalink();
						$posttitle .= '" title="';
						$posttitle .= __('Permalink to ', 'thematic') . the_title_attribute('echo=0');
						$posttitle .= '" rel="bookmark">';
						$posttitle .= get_the_title();   
						$posttitle .= "</a></h4>\n";
						echo $posttitle;
 
						the_excerpt();
					?>
 
				</li><!-- .post -->
		<?php
		endwhile;
		echo '</ul>';
}
add_action('thematic_above_indexloop','featured_posts');

ul#featured-posts {
    float: left;
    margin: 0;
    padding: 0 0 15px 0;
    list-style: none;
    color: #111;
    font-size: 11px;
    line-height:14px;
    font-family: Helvetica, Arial, sans-serif;
}
#featured-posts li {
    float: left;
    width: 135px;
    padding: 12px 10px 10px 10px;
    margin-right: 15px;
    min-height: 260px;
    background:#f1f1f1;
    border:3px double #ccc;
}
 
#featured-posts li p {
    margin: 0;
    padding: 0;
}
 
#featured-posts li:hover {
    background:#fff;
}
#featured-posts li h4 a {
    font-family:Georgia, Times, sans-serif;
    font-size: 12px;
    line-height: 13px;
    display: block;
    padding: 5px 1px;
    color: #111;
    font-weight: bold;
}