He uses the <marquee> tag. Basically what you do is put whatever you want in the <marquee> tag and it will scroll.
This is what Urusai did:
<marquee onmouseover="this.stop()" onmouseout="this.start()" scrollamount="5" scrolldelay="50">
...
</marquee>
You probably want to add a width and height to that by adding width="..." height="..." after marquee.