Schneider Digital's driver is the one driver I haven't tried myself, but it seems like a serious attempt on making a decent ATI Radeon driver for Linux. Well, enough chatting, let's get down to business.
First, download the driver file for either XFree86 4.1.x, XFree86 4.2.x or XFree86 4.3.x..
The installation instructions for this driver are exactly the same as for Section 4.2, so follow those.
Congratulations, you are now up and running! Please let me know about your experiences with this driver, as I didn't try it myself.