AMD has released the next version 9.12 of its ATI Catalyst display drivers for Linux. The drivers can be download from ATI Catalyst™ 9.12 Proprietary Linux x86 Display Driver Page. As of now, I haven’t tried the drivers on Fedora 12 because supposedly my SMPS is broken But since there were a whole lot of bug reports to AMD regarding xorg 1.7 and catalyst, they might have fixed it. Please try and let everyone know if these drivers work with Fedora 12. You know where the howto for installation is How To: Install ATI Catalyst (fglrx) Drivers.
Also, if these drivers doesn’t work, a lot of people are finding mesa-drivers-experimental a huge success over catalyst drivers. Don’t miss those experimental drivers. Checkout comments on Fedora 12 ATI Catalyst Drivers.
Anyway, let us know whatever works for you