We can’t verify the authenticity of this information, but there are images that supposedly come from a debug menu in iBook from an iPad 3 prototype. Right now, they have found that the current prototypes are one iPad in two versions. The first is wifi-only and the second is GSM,CDMA and LTE-enabled.
Also noted is that the iPad 3 will have an A6 processor (expected) and that it will be quad-core. This has also been rumored many times in the past. What we don’t know is how the case design will look. Most rumors and speculation say that it won’t be far from what the iPad 2 is. The device is likely to be very similar in appearance. Obviously, we can’t know that yet, but it makes some sense given Apple’s history with the iPhone. They typically give it a couple of years before they significantly change a design.
Apple is expected to introduce the iPad 3 this spring. Perhaps March or April with a release soon after. It’s likely that the new device will have a high-resolution Retina Display like the iPhone 4 and iPhone 4S. Rumors have also said that the tablet may be equipped with a camera similar to what’s found on the iPhone 4S.