ATI has released a newer version of the Catalyst drivers which includes support for the OpenGL Shading Language.

OpenGL Shading Language Support:
This release adds support for the OpenGL Shading Language (GLSL), a flexible, forward-looking, and hardware-independent high-level graphics programming language. The OpenGL Shading Language, defined as an open standard by the OpenGL Architecture Review Board, allows application developers to take advantage of the powerful programmable vertex and pixel processing units present in the 3D graphics system. Open languages offer developers the fastest route to using the latest graphics hardware features.

You can download the driver from the links below.

-ATI Catalyst Radeon Display Driver 3.10 (Windows 2000/XP)
-ATI Catalyst Radeon Display Driver 3.10 (Windows 98/ME)

Thanks to Didou for bringing this to our attention.