We've had a thread about this game before, but our guess is that the game is coming within the Spring 2009 time frame (it wasn't apart of Spring Fever). Since it's technically not Spring yet, it should be out anytime from Mid March to Mid June. I could have sworn I heard Jeff R. at the PS Blog say wait for GDC to hear something.
Since the ESRB.org rated this game over a month ago, I definitely say its not too far off.