Popup pictrures (light window?)

Alright, in the process of creating my website, I had someone in my graphics class show me how to display images on a website more cool and effectivly. He called it something like a "light window" or something. Here is an example of what i'm talking about.

http://www.seethingdesigns.com/gallery.php

when you click on the pictures a little popup of the picture comes up. He said it was in javascript.

Anyone help?

 

Lightbox

sorry i didn't reply earlier, internet's been down.