Yeah xgl is linux only, vista will include such features but will need latest hardware to run, this stuff runs on very limited hardware like some 500mhz p2 and 256mb with nvidia mx400 (this are not minimum requirements just some pc wich i tested it on before installing on my main system.)

Updated just managed to configure the skydome.
And fyi I'm not a linux guru just a regular user with not much knowledge but there are how to's, forums irch channesl and great thing about linux is that everyone is willing to help, i use it as seconday system just because some 3d appz i use are windows only that's why on this pc win xp and linux coexist on different partitions.

Ubuntu forum a complete thread about xgl and how to get it running on latest ubuntu release:
http://www.ubuntuforums.org/showthread.php?t=131267&highlight=xgl

This is compiz forum, they have a how to section on how to get it working on different linux distros in case you are using other distro than ubuntu, good luck and specially have fun while doin it, it took me a few hours to get mine running and properly configured but finally it worked and whilst it can be frustrating some times for us unexperienced users in the end you get the satisfaction of knowledge and being able to say hey ma look what i did .

Windows is selfdestructive. It's fucking hilarious using it Linux is the way to go and Ubuntu is a good choice. About the "I don't know anything" part there is a forum for noobs as it was mentioned. If you want to do something but you don't know how it will take you 10-30 minutes to figure out how. But the next times it will take you 2 seconds to make it work.

Just remember one thing that is important to me (at least that's how i work): Keyboard and console are your friends, the rest slow you down.

It's like in q3, when you want to load a map you browse through them or drop the console and type /map q3dm3 ?

I've seen a pc that stayed on for four years with Linux on. They turned it off to move it to the other side of the town. Can you imagine running Windows for more than a few days and not restarting? Or writing a cd, burning a movie, playing a game and all run smoothly

Oh yay that along with the youtube stuff made my day

If you know someone in rl who uses linux get him to help you out. Otherwise, gather as much information as you can on the net and then go from there.