Four AA batteries, which are included, power the Remote Keyboard, and Microsoft claims that will keep your unit operating for three months, depending on the amount of use, of course. To conserve battery power, you can opt to turn off the backlighting. There's also a security switch on the front of the keyboard that locks down the keys to prevent accidental strokes when not in use.
The keyboard will work with any PC running MCE 2005, but you'll need to download an updated driver from Microsoft's Web site (the driver is not included with the keyboard) to enable communication between the keyboard and your Media Center's built-in receiver.
Microsoft offers a three-year limited warranty on the hardware and free phone and e-mail support for the first 90 days; after that, support will cost you $35 per request. Online self-support, downloads, and updates are also available via Microsoft's support Web site.