in header.php find:

<h1><a href="<?php echo get_option('home'); ?>/"><img class="logo" src="<?php bloginfo('template_directory'); ?>/images/logo.png" alt="<?php bloginfo('sitename'); ?>" /></a></h1>

and replace it with:

<h1><a id="heading" href="<?php echo get_option('home'); ?>/"><?php bloginfo('name'); ?></a></h1>

Thats it.