<div class="searchform">
<form method="get" action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']); ?>">
<p>
<input type="text" name="s" id="searchbox" />
<input type="submit" src="<?php bloginfo('template_directory'); ?>/images/searchbutton.jpg" id="searchbutton" value=""/>
</p>
</form>
</div>