You can buy the Power Keyboard in black for $149 with free shipping from the Microsoft Store. It is not only a QWERTY keyboard that quickens your typing speed by 50%, it also is a protective case that protects your investment from drops. It also will prop up the screen at a better viewing angle for videos, or just to read a report that you've been working on.
The Power Keyboard comes with a 2027mAh battery to increase your slab's battery life by 50%, and also is equipped with two full size USB ports. It's quite a handy accessory to own, especially if you're a power user. Keep in mind that it is available only for the Nokia Lumia 2520 slate.
source: Microsoft via WPCentral