Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Kubuntu is a KDE version of the Ubuntu distro which is Gnome based. It is actually more like a Debian install of the "unstable" branch. That doesn't mean the system is Unstable it just means it's a Debian install with the most recent "cutting edge" versions of the softwares. For more info on the Debian way of thinking about package handling check their package page at the Debian site. Of course Kubuntu is completely free as per the Debian social contract.
First of all you'll need some decent hardware. Kubuntu will require some decent hardware to take full advantage of the feature rich KDE environment. As my test bed I'm running it on a 500MHz Celeron with 392MB of ram and an Nvidia Riva 128 Video card. That's pretty conservative hardware and it runs fine. I also am running it on an AMD 2GHz Athlon system with 512MB of ram and a Nvidia 5200 Video card. That's what I'm typing this How-To on. Both systems run fine with no problems. The Athlon system has even loaded and played Games with Cedega. I played PainKiller and Unreal Tournament with no problems at all. There is a screen shot of Painkiller in the Gallery. It could use some more ram but that's a personal preference more then a requirement. It has encoded Video with DVD::Rip without any problems. (This is where that extra Ram could come in handy) All in all the system runs great.
So lets get to it!!