Once you've got MySQL and php installed you're ready to install phpNuke, which is why I bothered mucking about with any of this in the first place. I quickly learned something about phpNuke though: its installation instructions suck. For a *nix newbie they're downright obtuse. Fortunatelly the installation instructions for Geeklog are extremely clear, very step-by-step, and pretty much identical to what you need to do to get phpNuke installed

My advice if you're planning to install phpNuke under X: download both phpNuke and Geeklog. Use the instructions from Geeklog to install phpNuke. Wash, rinse, repeat.