you can use tubenow linkchecker the HTML version. been using it on my wordpress based sites.

http://tubenow.net/link-checker-addon/

Code: 
<form action="http://tubenow.net/link-checker/" method="post">
<textarea style="border: 1px solid #9d9d9d; background-color: #d3d3d3; color: #000;" rows="10" cols="45" name="links"></textarea><br />
<div style="margin-top:4px;">
<input style="padding: 2px;" type="submit" value="Check Links" name="submit" />
</div>
</form>
Place it on single.php after <?php the_content(); ?>