This is just a directory, nothing more! It just requires that you add a meta tag to the head portion of your index page html, this allows the directory to know where to put your site within the directory. The only thing "Special" is that it give you a nice PR link and you get it right away (if you know how to add the meta tag)
Somewhere in the site is a place where you can get the category code that you need to add into your header, I haven't done it for a while so I can't explain where. Once you get the code into your html header you have it chack the code and it will then enter you instantly.
All you need to do is find the cateogry that best suits your site. Then, enter your URL in the field located on the upper-right hand side of the page. Take the code it gives you and insert it under the meta tag (in between the <head> tag) in your index page.