Comment 79 for bug 148408

yes I'm able to use it in hardy. one problem is the installation with
dpkg --force-conflicts -i xserver-xorg-video-ati_6.6.3-2ubuntu6_i386.deb because of the
provided xserver-xorg-video-1.0. hardy xserver-xorg-core conflicts with this.

Xorg.0.log:
(II) LoadModule: "radeon"
(II) Loading /usr/lib/xorg/modules/drivers//radeon_drv.so
(II) Module radeon: vendor="X.Org Foundation"
        compiled for 1.4.0.90, module version = 4.2.0
        Module class: X.Org Video Driver
        ABI class: X.Org Video Driver, version 2.0
(II) LoadModule: "ati"
(II) Loading /usr/lib/xorg/modules/drivers//ati_drv.so
(II) Module ati: vendor="X.Org Foundation"
        compiled for 1.4.0.90, module version = 6.6.3
        Module class: X.Org Video Driver
        ABI class: X.Org Video Driver, version 2.0

But I builded the binary from the source of 6.6.3-2ubunt6
Maybe give this a try.