The Apple Wireless Keyboard (AWK) works with BlueTooth, and you need to make Linux able to talk with it this way. I got one with a cheap adapter from RadioShack. First thing is that you must make sure that Linux recognizes the adapter itself. If it is an internal one, search and check for its chipset.
As I was using BlueTooth for the first time on a computer, I found that under Linux, any device that is attached by BT must have a name. I could not get mine to remain connected, until a friend of mine connected it to his MacBook. It then got his name (automatically) and I could get it working just fine under Linux (Ubuntu 8.x). I just got it back so that he changes the name to a generic description (AppleKeyboard).
Hope this can help.