According to the report, the game - which was released on August 25 - has already moved "nearly two million units in less than a month" and calling it a "major hit".
Technically, the game has been out - as of today - two weeks and two days. That's about a million per week.
Not too shabby. the NPD figures are released today, so we may get an actual number for it later in the day.
More through the link, via Joystiq.