How do I set up a bluetooth keyboard on my Mac OS X system?

It's Apple, it's a Mac. Of course it's easy to do! :-)

Seriously, while bluetooth might be a bit of a mystery to most people, all you really need to know about it is that it's a short-range wifi-like network. Mostly it's used for cellphones as a way to connect with headsets, but it's now also used for keyboards, mice, and even data transfer between devices.

But let's get back to your scenario, because it's pretty straightforward once you realize you need to enable bluetooth to start, and when you do, you'll see there's a little wizard...

Start by going to System Preferences off the Apple menu and click on Bluetooth:

Once you launch, odds are pretty good you'll see something like this:

You'll need to both turn on Bluetooth (click the box next to "On", then click on "Set Up New Device..."

The wizard, uh, bluetooth setup assistant launches:

Make sure that your new keyboard is turned on (push the button on the right side of the top of the keyboard, in this case), and after a few seconds you should see the keyboard show up on the list:

Choose it then click on "Continue":

At this point you need to type in the digits, digit by digit, as shown. As you type them, the next digit you need to type is highlighted in blue. Type 'em all in, then press Return and you'll be all set up:

Sweet. Now when you go back to the Bluetooth setup in System Preferences, it's a bit different:

There ya go. Enjoy the bluetooth keyboard and know that this is the same basic strategy you want to use for a bluetooth mouse too, if you hook one up, or headphones, for that matter.