Debian Installation Guide

As of November 2005, ATI's drivers are in the non-free area of Debian. Make sure your /etc/apt/sources.list contains "contrib non-free" as well as main. You will, however, have to build your own kernel modules.

Install the driver
sudo apt-get update sudo apt-get install module-assistant fglrx-driver

Compile the kernel driver
sudo module-assistant prepare sudo module-assistant update sudo module-assistant a-i fglrx

Update the xorg.conf file
sudo aticonfig --initial

Now restart X, or reboot for the driver changes to take effect.

Confirm that it worked
$ fglrxinfo display: :0.0 screen: 0 OpenGL vendor string: ATI Technologies Inc. OpenGL renderer string: MOBILITY RADEON 9700 Generic OpenGL version string: 1.3.5461 (X4.3.0-8.19.10)