ref:
http://forthewiin.org/
http://doc.ubuntu-fr.org/wiimote

For Ubuntu 7.04
1. 
sudo apt-get install autoconf autotools-dev libbluetooth2-dev libgtk2.0-dev mouseemu bison flex gawk

2. create cwiid packages and install them
in /etc/apt/sources.list, add
deb-src http://free.nchc.org.tw/ubuntu/ gutsy main restricted universe multiverse
sudo apt-get update
sudo apt-get build-dep cwiid
sudo apt-get source cwiid
cd cwiid-0.5.03+svn20070508/
dpkg-buildpackage -rfakeroot
cd ..
dpkg -i *.deb

3.
sudo modprobe uinput
(better to put it in /etc/modules)

and /etc/udev/rules.d/40-permissions.rules
# Steven added:
KERNEL=="uinput", MODE="0666"

4.
and we can find the Bluetooth peripherals address by:
sudo hidd --search

5.
To use it as a mouse:
wminput -c acc_ptr 00:19:FD:50:B5:24
Then press 1 and 2 simultaneously in wiimote 

6. /etc/X11/xorg.conf
   add:
Section "InputDevice"
        Identifier      "Wiimote"
        Driver          "evdev"
        Option          "Name"          "Nintendo Wiimote"
EndSection

Section "ServerLayout"
	Identifier	"Default Layout"
	Screen		"Default Screen"
	InputDevice	"Generic Keyboard"
	InputDevice	"Configured Mouse"
	InputDevice     "stylus" "SendCoreEvents"
	InputDevice     "cursor" "SendCoreEvents"
	InputDevice     "eraser" "SendCoreEvents"
	InputDevice	"Synaptics Touchpad"
	InputDevice	"Wiimote" "AlwaysCore"       <------
EndSection