Ok - Sorry for the delay, here is what we know as of now:
First off, we're not sure how long that site will actually be around since it's being hosted on a free domain. (co.cc) The site itself and the pictures are owned by the same people that own a number of Japanese delivery health agencies around Tokyo. It's kind of hard to easily demonstrate how they are all connected, but their main shop appears to be this one:
http://www.dk-shinjuku.com/
They also own:
http://www.de-prism.jp/
The site in question was created sometime in July '10 and has had a few updates since that time.
As for the girls pictured or actual service provided, we don't have any hard evidence. We don't exactly have the budget to send people out to try these places.
There are seven major players in the Tokyo delivery-health market, they control most of the legal Japanese shops. Everything else is small potatoes or owned by a single person or group of people.
Our best guess: Japanese shops are wanting more of the foreigner market and therefore springing up English sites to attract foreigners. Oddly, as you may actually expect, they are still discriminating against other Asian ethnic groups such as Chinese. If you're a typical white, westerner, you're likely to be offered service while others will not.
If any more information becomes available, we will pass it along.
EDIT: Not all that useful, but here's one of the sources of pictures. Probably the photographer or owner, cannot fully confirm.
https://picasaweb.google.com/105045449107538831519
