That's right, not only is Six Flags Great America in Gurnee getting a new roller coaster, but it's going to themed after Batman: The Dark Knight. Not sure if this will replace the current Batman coaster. Here's a quick description from the Six Flags website:

Venture through demented hallways of twists, turns and hallucinatory images, while being tormented by The Joker himself......You can only guess at what awaits as you speed through six 180-degree hairpin turns, climb unseen hills, plunge into pitch darkness and dip into unforeseen danger. As you attempt to escape the terror, your only hope is that Gotham's Silent Guardian — Batman — can save you!

You can read the full descrip here. Aint It Cool News has some leaked design art for the ride that hasn't been released yet. See that here. Looks awesome!