Well if you have not hosed your system yet and still have Gnome up and running.
Here is a easy way than using the install CD. It is very quite simple really.
You will not believe how simple it is. Here is the link and you'll go. Wow that
is very simple! A good internet connection is a must. The reason why, is that it
is going to install KDE from the net.
http://www.psychocats.net/ubuntu/kde