When Apple will release the next iPad and what form it will take when they do are only at the theory stage, but smart money says that Apple will release it in the same time table they do every year: March or April.
However, according to Citi analyst Richard Gardner, we may get it a bit early: February 2012. And when it comes, “several sources” have confirmed it will have a Retina Display.
Otherwise, what we know about the iPad 3 is mostly speculation, though it seems likely at this point that it will be slightly thicker than the iPad 2 in order to accommodate the dual LED lightbar necessary to illuminate the Retina Display. That means it won’t be backwards compatible with iPad 2 cases, though the Smart Cover will still work.