The Steven Spielberg fansite, SpielbergFilms.com reports on the status of Jurassic Park IV.
The site has squashed the recent rumors that some of the cast has already been chosen for the film:
Steven Spielberg's personal reps at Amblin Entertainment (co-producers of the Jurassic Park franchise) have told SpielbergFilms.com that casting has not commenced on the film, as the story and screenplay are still in development. While there's been talk over the years with series stars Sam Neill, Jeff Goldblum and most recently, Laura Dern, the property is still not ready to move forward toward production and no casting is taking place.
The site goes on to say that the film is still in development, but it's not near the point that these rumors would have it.