I have installed the AMD driver in 12.04 using the Additional Drivers function. It works fine, fglrxinfo returns correct information, but it seems that there is no Catalyst Control Center, I tried installing fglrx-amdcccle, but still it does not appear when I search installed programs.
Just run
amdcccle
from terminal, you can also make a shortcut, to run as root usesudo amdcccle
.This line will open the AMD Catalyst as Administrator (you will be prompted for superuser password to use it (your root password)
Are you using the Unity panel or the default Gnome? Install Gnome Shell and then do a search for "AMD". If this still dosen't work, try installign it from Synaptic Package Manager.