I watched the first (and best) Jurassic Park recently and I was surprised at how well it looks, almost fifteen years later. Fifteen years, man do I feel old. The Lost World was a terrible film, and the book is even worse. I hope that to this day, Steven Spielberg and Michael Crichton feel ashamed for being behind such terrible work. Jurassic Park III wasn't bad, but the ending seemed to be missing. It's almost as if Joe Johnston decided to drop a reel, Grindhouse style.
Producer Frank Marshall spoke with comingsoon.net and he hoped that the next film in the dino-franchise would be released in 2009. He's quoted as saying "There's an idea and we just have to see if it shakes out".
I'm sure we will find out more after the writer's strike. If it ever ends.