Perhaps they said in your newsletter that they now allow IDNs. This does not mean that they have not already allowed them, but is probably more of a ploy by them to get you to register them. Godaddy is always reminding you of services that have existed forever, I can't register a name without being redirected to a page first that says "Do you know that Godaddy now offers Traffic Blazer, buy it now for only this much" or "Do you know that Godaddy now offers some other product", which has actually been offerred for a long time. It is just their way of trying to induce you to buy them.
I will say this, I registered my first IDNs at Godaddy on 4/14/2007. They also gave me no impression at the time that it was a brand new feature or anything like that. That is why I say that they are not newly offered available to register.
