The second beta of KDE SC 4.4 has packages available in our Beta PPA. There are also betas of Amarok and KDevelop available.
Users of our latest development release, Lucid, can upgrade to the latest packages.
Users of our stable 9.10 release can install it from the Kubuntu Beta PPA.
deb http://ppa.launchpad.net/kubuntu-ppa/beta/ubuntu karmic main
Then do sudo apt-get update then sudo apt-get dist-upgrade and sudo apt-get install kubuntu-desktop.
It is strongly recommended that you verify the integrity of these packages by installing the archive's GPG key. You may do this by following the instructions on this page.
Many thanks to Lex for his hard work on these packages.