Actually,Ubuntu 's default ATI driver can enable some Compiz effects already,but the default driver's effect is not good,so we use below ways:
We may install open source ATI video card driver : System->Administration->Hardware Drivers,tick the driver you need ,and then click it to intall.
Intall ATI official driver,below is the download link :
All series of ATI video share same linux driver,so you don't need to choose relevant model number.
cd /home/(your user name)/Downloads
and then run:
(Pls note that the filename of driver might be different due to version change )
chmod 777 ati-driver-installer-10-6-x86.x86_64.run
and then run it again:
Click "system->preference->apperance->visual effects",choose "none" on most top.
then,click"System->Administration->Synaptic" and seach"compiz" in Synaptic.All below packages must be installed
Click"Application->System tool->compiz fusion icon" after finishing installation ,then you may see there is a blue icon on right top of the screen.
last step is configure the Compiz, just move your mouse arrow to the fusion-icon's icon and right click mouse->Setting manager to choose effects you want to enable.If you come cross any problems after configuration,please try to reboot your computer.