jquery show/hide div not working

Hi all,

I have an e-comerce site build over a WP + e-Commerce with a premium theme I bought and I have a little problem with a little script that should hide one div and it does not. The code is this:

<input type="button" value="+/- Información" onclick='$("#nombre_div").toggle(200);'>
<div id="nombre_div">
      <div class="wpsc_description">
                  <?php echo wpsc_the_product_description(); ?>
      </div><!--close wpsc_description-->
</div>

I have added a call to jquery in the header although I think it is included in Wp by default. I explain that this div (wpsc_description) is the one that shows the description of every single product in the products page. Maybe the IDs should be dinamic instead of static? I don’t know what’s wrong, If I use it in an HTML file (same server) works perfectly.