Installed ANSYS 11.0SP1 and 12.0.1 on fresh install of Ubuntu 9.04 Desktop (32-bit and 64-bit).  Except for needing to install the libmotif3 package (available in the repository), there weren’t any additional steps needed, and I was able to run/solve ANSYS fine (both x11 and 3D (OpenGL/Mesa)).

(Supported/tested Linux distributions are listed in the ANSYS Installation and Licensing Guide, and required packages are also listed there.  Note that Ubuntu is not a supported distribution.)