One of the resources I’m drawing on for my Ghostbusters adventure, The Lurker in the Limelight, is a fan supplement written for the d20 Modern system, Michael Tresca’s Ghostbusters: Who Ya Gonna Call? It’s a very elegant PDF, downloadable for free from his site.
Admittedly, I’m using GURPS as my system of choice, so the stats aren’t of immediate utility, but this PDF is really helpful as a guide to what might be useful to the average ghostbusting PC. Sure, we all remember the endless font of information that was Tobin’s Spirit Guide, but what about The Roylance Guide to Secret Societies and Sects or Who’s Who and What’s That?
The reminder that ghostbusting can easily become an extra-planar activity alone gave me some terrific ideas. So thanks, Michael, for taking the time to write your PDF and share it with the gaming community.
Held Action 
My pleasure. 🙂