BTW, I've just tryed out ATI drivers on X300. 2D seems to be more responsive (but this might be purely subjective, I've not run any benchmarks), and of course there's also 3D acceleration. Installation is not for the faint of hearth indeed. Shame that people working for free in their spare time are polishing their software more than paid programmers.
Make sure you donwload correct version of RPM (i386 or x86_64). Uninstall xorg-x11-Mesa-libGL (ATI RPM containst those libs too). You'll need to use '--force', and on x86_64 you'll also need --allmatches (in case you had both i386 and x86_64 lib installed). Install ATI RPM package. The x86_64 ATI RPM has both 32-bit and 64-bit libraries, so you need only one RPM, don't try to install both i386 and x86_64.
After installing RPM, you need to reconfigure xorg.conf. Documentation points to non-existing fglrxconfig. It was replaced by aticonfig (found it with little Googling), but documentation was not updated. Simply run:
# aticonfig --initial --input=/etc/X11/xorg.conf
Then make sure devel package for current kernel is in place (make sure to use smp devel package if running SMP kernel). Execute (replace KERNEL_PATH to match kernel version, architecture and SMP or non-SMP).
# cd /lib/modules/fglrx/build_mod # KERNEL_PATH=/usr/src/kernels/2.6.9-34.EL-smp-x86_64 sh make.sh # cd .. # sh make_install.sh
You will get an error in second step. *Ignore* error as long as you get instruction to execute make_install.sh in parent directory! Took me a bit of Googling to find that out.
You can kill your X server now. After logging in, lsmod should show fglrx is loaded. fglrxinfo should show "ATI" in OpenGL vedor string.
There's still couple of gotchas I'm figuring out. Like resolution defautls to highest my card/monitor combo supports (1792x1344 hurts eyes on 19" monitor). I'm able to change resolution only for current user by going to Applications->Preferences->Screen Resolution. I guess there's option in aticonfig to set that up, haven't looked yet. Try running fgl_glxgears, it should be fast.
Anyhow, seems to be working, if 3D is required...