Fedora 13 Installation Guide
ATI's latest Catalyst 10.7 now supports Xorg-server 1.8 after our 3-month wait. Fedora users should of course be used to this.
Although 10.7 is designed for OpenSUSE 11.3, it supports all other distros using Xorg 7.6 like Fedora 13 and Ubuntu 10.10.
Just download the .run installer, run it using root privileges, follow the instructions on the screen and reboot.
Maybe you should add a 'nomodeset' parameter in the grub entry, or you might encounter a black screen hang after plymouth, at least on my laptop.