http://hollywoodinsider.ew.com/2009/04/ghostbusters-ii.html
Key bits being:
But now theres a new concept,“ Ramis says. ”And its interesting, beyond the kind of mythology of it, theres a personal story thats pretty grounded."
And yes, the original cast will return: Dan Aykroyd, Ernie Hudson, Rick Moranis, and even the elusive Bill Murray.
I'm sure the part about Moranis is just making an assumption, but hey we can hope right? Even though it is very little info about the story itself it sounds pretty cool.