Pretty simple. Edit storytext.thml, featuredstorytext.html, and archivedstorytext.html in your layout directory. These are the templates for how introtext is displayed
Text Formatted Code
<div class="story-footer">
{edit_link} {page_selector}<br>
{readmore_link} {post_comment_link}<br>
{start_comments_anchortag}{comments_with_count}{end_comments_anchortag} {start_trackbacks_anchortag}{trackbacks_with_count}{end_trackbacks_anchortag}
</div>