Okay, I am by no mean a "real" developer, but I made a .deb file for the latest Scrivener for Linux beta (2.9) from the latest tarball. This should install on 32-bit Ubuntu 11.04 (and Ubuntu-based distributions) with a double-click. See below for instructions for installing on 64-bit systems. See the "attachment" link at the bottom of this post to download.

(Since OS X is *nix-based, some have asked why it wasn't ported over from the Mac long ago. Easy--It was originally written in Cocoa, meaning that it had to be re-written from the ground up for Linux and Windows, which couldn't happen until the creator hooked up with the right Windows/Linux developer.)

For 64-bit systems:
sudo dpkg -i --force-architecture scrivener_0.2.9_beta.deb

Important: if you want spellcheck to work on 64-bit systems, before installing Scrivener, download getlibs from here http://frozenfox.freehostia.com/cappy/ and install it.
Once getlibs is installed, run the following commands:
getlibs -p libaspell-dev
and
getlibs -p  libaspell15

Either way, it should also make a launcher in the office section of your main menu, but you may have to edit the launcher to include the icon.