"Nitrox" and the developer Sonic Lion seem to be long gone, sadly. The links on this page go nowhere, and a Google search did not turn up any new links for the software. (Not too surprising, since this software came out 4 years ago.).
Perhaps worse is the site exists, but fails to register people. It would be better if it had vanished. After getting one email blocked for a mistype, and getting another registered after fighting with a fairly ugly captcha, but receiving no validation email to the account, I'm beyond fury. I want those minutes of my life back.