4. Tap the name of your Bluetooth keyboard when it shows up on your
iPad. A Passkey number will be shown on the iPad. Type this number
on your Bluetooth keyboard and press "Enter." The iPad and keyboard
will now be paired.
Notes:
a. To reconnect when disconnected, simply press any key when within
range of your iPad.
b. When the keyboard is connected, the onscreen keyboard will
automatically be disabled. To bring up the onscreen keyboard, press
the Eject key.
c. To disconnect the keyboard, simply go to Settings =>
General, and turn the Bluetooth radio off and on. (as of iOS 3.2.2)