According to Take Two CEO, Strauss Zelnick, Grand Theft Auto IV is still scheduled to be released between the beginning of February and the end of April. Earlier this week Zelnick stated that he wasn't willing to give a precise release date, which started some rumors.
Gamespot has done an interview with Strauss Zelnick, in which he states that releasing the game after the Christmas season won't hurt their sales, and that it is great if you can buy "terrific" games during the entire year. Zelnick went on to say that this would be a good thing for the industry and not just Take Two.
Zelnick also added that the date will come as soon as "they feel very comfortable" that they know the exact date within that three-month period, better known as the second fiscal quarter.