oion is correct.
In addition to the Power Cover due in 2014 (which is thicker than the current Type Cover 1 as well as the newly announced Type Cover 2), Microsoft demonstrated the Type Cover 2, which is an upgraded Type Cover attachment for the Surface Pro 2 tablet. It is thinner as a whole millimeter has been shaven off, but it isn't any less functional. In fact, the Type Cover 2 is silent and sports a backlight. It will be available in purple, pink, blue, and black. I pre-ordered a black one incidentally, and will likely explore the Power Cover in stores when available. The Power cover will also be compatible with Surface Pro 1 - and as oion mentioned is not yet available for pre-order.