Dreamweaver - Adding a scrollbar into your HTML / CSS

Hi! I am making a web page that I'd like to have a scrollbar inside of the window (not the normal scrollbar). I've seen this before, for example, on www.nothingvideos.com. This is the same thing I am trying to do. I just have a window inside of my page that I want users to be able to scroll in. Any ideas? I created my HTML from a graphic I created in PS using Fireworks, sliced a square, then removed it and created a CSS w/ that image cut out as the background.

I think you can do that with Iframes but I never did it.

Color them using CSS, like this:
http://www.websitetips.com/info/css/scrollbars.html