Ghostbusters 3 and 4 announced. Bill Murray in For GhostBusters sequels

In an exclusive interview with franchise director Ivan Reitman, sources say that Bill Murray has finally agreed to reprise the character of Dr. Peter Venkman and team up with Dan Aykroyd,Ernie Hudson and Harold Ramis for not just one, but two 'Ghostbusters' adventures. They are set to be filmed concurrently and released back-to-back for Christmas 2012 and Christmas 2013.

Bill Murray has finally given the go ahead to star in The Ghostbuster sequel.  Not just one, but two of them.

Sources have also confirmed that the movie line will involve the original cast training a new era of Ghostbusters.  If the movie is a success there have also been talks of a spin-off.  This could be the worst thing to happen to a movie franchise since Scream 4 was announced.

As was previously speculated, the plot of 'Ghostbusters 3' and '4' will focus on Venkman, Egon and Ray Stantz training a new generation of Ghostbusters. If fans respond positively to the young cadets, Sony also has plans to move the series forward with their own movie in the future.

According to Vanity Fair, actor Dan Aykroyd has decided to take the reins in writing the script for 'Ghostbusters 3'.  The original script was written by Gene Stupnitskyand Lee Eisenberg.  The pair are writers on 'The Office' and also wrote the movie 'Year One', which 'Ghostbusters' star Bill Murray publicly bashed in an interview with GQ. 

I think he was concerned that the writing on Ghostbusters 3 by these guys would not be up to standard, but I can tell you firsthand, I’m working on the script now and those two—Stupnitsky and Eisenberg, [writer-producers of The Office]—wrote Bill the comic role of a lifetime, and the new Ghostbusters and the old are all well represented in it. We have astrong first draft that Harold [Ramis] and I will take back, and I’m very excited about working on it.

Look, Hollywood is in love with any kind of nostalgia that can prove itself to be commercial. But it has to evolve. Now [in Ghostbusters 3] my character’s eyesight is shot, I got a bad knee, a bad hip—I can’t drive that caddy anymore or lift that Psychotron Accelerator anymore, it’s too heavy. We need young legs, new minds—new Ghostbusters; so I’m in essence passing the torch to the new regime, and you know what? That’s totally okay with me.