Decided I needed a decent FPS on my machine, and since I had a copy of UT2003 laying around, thought I'd try to install it in Ubuntu.
This is the process that seemed to work for me:
Insert disk3, copy "linux_installer.sh" to my home dir, open a terminal in the home dir, and run:
sudo _POSIX2_VERSION=199209 linux32 sh ./linux_installer.sh
follow the gui installer :)