Ionut was so far ahead of this news that it hasn't even happened yet. He tells us that everyone in the world is now available to sign up for Gmail, but that's clearly not the case (yet). Even if I use the direct link to the signup page, it still asks me to log in without the option to create a new account.
However, there is very strong evidence that this will be happening sooner than later -- on February 5th, this help page was updated to state they have already "flipped the switch", even though they clearly haven't.
Anyone in the world is now welcome to create a Gmail account at http://mail.google.com/mail/signup. Enjoy!