Honestly the easiest way is just getting a Dolphinbar, It has the correct bluetooth adapter built into it. I got mine in the UK from eBay and after installing BlueZ and tinkering with some settings I got it to work perfectly with my launch model Wii mote + nunchuck.
I've only used it for normal Wii mote mode in Dolphin, But it has a mode to use it as a mouse + keyboard or generic gamepad.