This new keyboard is included with the new iMac but you can also order it in the Apple Store. There are two flavors: wired and wireless. The wired Apple Keyboard costs $49 and the wireless one $79.
The Apple Wireless Keyboard has been completely redesigned, inside and out. It features an elegant, ultra-thin anodized aluminum enclosure with low-profile keys that provide crisp, responsive feel. It also has function keys for one-touch access to a variety of Mac features such as screen brightness, volume, eject, play/pause, fast-forward and rewind, Expose, and Dashboard. Its compact design fits on your lap or on even the most crowded desk. And its Bluetooth wireless technology lets you use it just about anywhere within 30 feet of your Mac.
The keyboard automatically powers down when you're not using it and turns on instantly as soon as you start typing. This intelligent power management means you'll get up to nine months of battery life based on average usage patterns. It also has an on/off switch for when you're away from your computer for a long time.