Removing Pages From Google Using Webmaster Tools

[Gracia]

Has anyone tried this out yet?
I have a site that I have no idea how it got indexed (it is just an IP, no domain name!) and I want to get it out of Google. I put up a robots.txt to ban access to the whole site 3 weeks ago and it is very slowly disappearing. I figured this tool is perfect for just getting the whole of the rest of the site removed quickly - put in the request and it has been denied. How useful!