Finding the Software
A quick search for "DVD on Linux" through google, provided me with a link to LiViD, the linux video project. A news item on the main page pointed me to the first official release of The Open Media System (OMS), LiViD's integrated DVD player.
It was only through timing that I found OMS, however - there was nothing else on the page indicating that OMS was probably what I was looking for. It was one of many projects listed on the side; someone simply wanting to start watching DVDs might have more trouble finding it.
Download and Installation
LiViD offered OMS either in binary (RPM, DEB, and tar.gz), source, or source via CVS forms - I downloaded the binaries and then grabbed the source from CVS. Installation of the binaries was a simple RPM -Uvh away (on Redhat Linux 7.1).
Source code compilation was a different matter altogether. The code needed kernel include files, but not just any kernel includes - they needed the kernel includes directly from the source. Redhat's "kernel-includes" package did not satisfy this requirement for some reason, and I ended up downloading the entire kernel.
Luckily, Redhat 7.1 ships with a 2.4 kernel, meaning support for the DVD filesystem (UDF) is built in, and I did not have to rebuild my kernel. 2.2 kernels, on the other hand, might require patching in order to work.
The DVD experience
After installing, I popped in my rental of "Alien" and started the program up. The interface is a fairly slick gtk based GUI, which was surprising to me. I had previously been under the impression that I needed to get DeCSS, crack the DVD, copy the file to my hard drive, and then play it. All these steps are automated under the new GUI, which certainly saved me a few headaches.
I ran into a problem very early on, however: it wouldn't play. The OMS Howto, luckily, had a link to a 'problems' page, where I found my answer: I hadn't set the region of my DVD player. (Software was provided on the 'problems' page to remedy this)
After setting myself to region 1, I started the GUI up again and pressed 'play'. Fanfare came through my speakers, and I watched as spotlights lit up the Fox logo. It worked.
Altogether, the installation was nearly painless, though it would be nice if the GUI would make it more clear that the DVD region needed to be set. The OMS Howto is an excellent guide, and they have a Wiki and an IRC presense to help with problems. I found that the SDL video target gave me a few more FPS, in addition to allowing full-screen usage, so it may be worthwhile to ensure that SDL is installed. In short, it wasn't difficult to set up and once setup was finished, it was effortless to use.