iKeyboard can turn your Mac into a Bluetooth keyboard for iPad/iPhone/Mac.

Pairing steps:
1. Mac : Select Discoverable in application menu.

2. iPad/iPhone: Select Settings-]General-]Bluetooth, you will find an avaiable
Bluetooth keyboard which name is your Macs computer name.

3. iPad/iPhone: Select your Macs computer name item to finish pairing.

Usage:

- Whatever keys you type on your Mac keyboard will be input into the connected iPad/iPhone.

- Use mouse to click any key button to send that key into the connected iPad/iPhone.

- Use connect menu to quick connect to paired devices.

Features:
- At most 5 devices can be saved.

- iKeyboard use F1~F12 for multi functions, please disable the F1~F12 hotkeys for your Mac.

- All keyboard layouts (US/JIS/ISO) can be detected.

ESC: Home button
FN+F1 : Search button
FN+F2 : Input method selection
FN+F3 : Apple Logo
FN+F4 : iPad slide show
FN+F5 : Show/hide virtual keyboard
FN+F6 : Lock button
FN+F7 : Previous song
FN+F8 : Play/Stop
FN+F9 : Next song
FN+F10: Mute
FN+F11: Volume down
FN+F12: Volume up

Trouble Shooting:
- Please make sure all your other bluetooth peripherals is connected before using iKeyboard. In case iKeyboard would close its connection.

- Sometime iPad/iPhone will mess up with Bluetooth stack. If you found
problems with paring with iKeyboard, please reboot your iDevices and choose Forget in Bluetooth setting and try again.

- iDevices can not be paired with two Bluetooth keyboards at the same time.
If you have already connected your iDevices to a physical Bluetooth
keyboard. Please disconnect it before you use iKeyboard.

- Sharing iKeyboard to MS Windows is not supported, yet.

Link for more information: http://itunes.apple.com/us/app/ikeyboard/id441439411?mt=12