KDE is built on the KDE Libraries which provide easy access to resources on the network by means of KIO and advanced visual capabilities through Qt4. Phonon and Solid, which are also part of the KDE Libraries add a multimedia framework and better hardware integration to all KDE applications.
First you need to edit the /etc/apt/sources.list file
sudo gedit /etc/apt/sources.list
add the following line
deb http://ppa.launchpad.net/kubuntu-members-kde4/ubuntu gutsy main
Save and exit the file
Update the source list using the following command
sudo aptitude update
Install KDE 4.0 in Ubuntu
First you need to remove any exiting kde4 using the following command
sudo aptitude remove kdelibs5 kde4base-data kde4libs-data
Now install kde4.0
sudo aptitude install kde4-core
This will complete the kde4.0 installation
you can run a full session by selecting "KDE 4" from your login manager.
To avoid having to start a second X server for a full session install xserver-xephyr and run Xephyr :1 & export DISPLAY=:1; xterm and run startkde in the Xerphyr xterm.
Once you logged in you should be able to see similar to the following screen
If you want 50 more KDE 4.0 Screenshots check here