I tested a Nissan 240sx with HICAS once and the rear wheels didn't turn at all, at least when it was parked. Something must have been wrong.
The Prelude rear wheels change their direction with the steering angle. When you turn the wheels slightly, the rear wheels turn in the same direction as the fronts, for changing lanes. It only does this on a short range of the steering angle. When you turn it farther, then the rear wheels turn the opposite way. It's pretty damn cool. Only problem is, it weighs ~200lbs more.
Dan