Here are a few simple steps to installing KDE 4.0.2. As usual I do not take any responsibility for anything that might go wrong.

This is how to install KDE on Ubuntu Gutsy:

1. Open your sources.list file from the terminal to add the new repository to the file:
   gksu gedit /etc/apt/sources.list
2. Paste this line of code to the end of the file to add that repositort to the file sources.list:
   deb http://ppa.launchpad.net/kubuntu-members-kde4/ubuntu gutsy main
3. Save the file, then close the text editor.
4. Now you have to update apt:
   sudo apt-get update
5. Now install KDE 4.0.2:
   sudo apt-get install kde4-core

All you have to do is log out and log in in a session of KDE.