Update: ATI AMD Catalyst 12.1 driver for Linux is available, you can check it here.
For smooth installation, it is recommended to uninstall currently availabe Catalyst driver. To do this, use these commands from the terminal:
sudo sh /usr/share/ati/fglrx-uninstall.sh
sudo apt-get remove –purge fglrx fglrx_* fglrx-amdcccle* fglrx-dev* xorg-driver-fglrx
To install the AMD Catalyst 11.12 Linux driver now on Ubuntu 11.10 (32-bit & 64-bit) or any older version, run this sequence of commands:
cd ~/; mkdir catalyst11.12; cd catalyst11.12/
wget -O ati-driver-installer-11-12.run http://goo.gl/BF35b
chmod +x ati-driver-installer-11-12.run
Then follow setup instructions:
Make now an update for the X.org file with this command:
sudo aticonfig --initial -f
Finally, reboot your system. Your driver is now installed on your system.
Note: Some users may not succeed in installing the driver due to hardware compatibility issues.
Warning: Install this driver at your own risk! We are not liable for any damage that may result from the use of this tutorial.