On Rev A's, which I believe what yours is, it was B.T.O.
On Rev. B it became standard.
You should know whether you have BT anyway, come on, iShane!
But, go into your Sys. Prefs, if you have a Bluetooth button - you have it. Also, try checking your menu bar, its next to AirPort, Clock etc as default.
If not, you can buy an adapter. But there is only 1 OSX certidied one, that works with the Appl KB's and Mice, the D-Link 120 I believe its called, on the Apple store anyhoo.