About the side navigation menu structure

Hi,
 
http://www.w3.org/Consortium/new-to-w3c.html
 
I am very interested in finding out how the navigation menu on the right hand side of your site was created using XSL. I would appreciate if you could direct me to a site or pages where I could learn more about how to achieve this.
 
kind regards,
 

Terry Dean
Terry.Dean@chariot.net.au
Tel: (08) 8344 5547