The first beta of KDE SC 4.4 has packages available in the Beta PPA. Ubuntu Lucid users can simply “sudo apt-get upgrade” to upgrade to the latest packages.

Ubuntu Karmic users have to add the following PPA (although I strongly advise you not to upgrade to KDE 4.4 beta, especially on a production machine):

sudo add-apt-repository ppa:kubuntu-ppa/beta

Then, if you are already using KDE (Kubuntu):

sudo apt-get update && sudo apt-get dist-upgrade

If you want to install KDE:

sudo apt-get update && sudo apt-get dist-uprade && sudo apt-get install kubuntu-desktop

Here are 2 videos with KDE 4.4 Beta 1 in action: