that uses a technology called Flash. What happens when you buy susch a template is that you receive all the relevant Flash files, ready to go - all you have to do is edit the HTML content to suit yourself.
Flash is a technology that uses vector graphics, and effectively makes little movies that run automatically - you create the files using Flash software, and some people find the learning curve a bit steep. Anyone can do it however, given the time and the patience to learn how to use the software, although a degree of creative talent is a big advantage.
Take a look at this, which explains things in a little more detail: