The new model which appears to be impossible to identify unless you fire the thing up and run a utility such as Geekbench to identify the exact model, which shows up as iPad 2,4. There are no indications of a new Apple part number being released for this new model
Reports suggest that the new model ships with a 32nm Apple A5 chip and provides an improvement of 15.8% in the battery life when surfing and 29.1% when gaming
This change has only currently been identified in the Wifi model and in both black and white units.
It does seem that Apple is keen to keep the iPad2 for sale for a while still!