While it initially seemed that fans ordering their copy of the Ghostbusters video game through Gamestop were only getting a t-shirt (a nice t-shirt mind you), Gamestop has sweeted the deal, according to their online store;
Reserve Ghostbusters and receive an exclusive in-game Ghostbusters 2 Flight Suit. The new suit updates your ghost busting look for the rigorous fashion standards of 1991, is more breathable than ever, and makes a statement of individuality without saying a word. This feature is available in single player and multiplayer modes. Available for online and in-store customers while supplies last.
Online Customers / Store Customers: Exclusive Flight Suit will come packaged with the game.
The bonus uniform appears to be available only for the Xbox 360 and Playstation 3. Thanks to Jokercard for the tip!