A second beta is out from KDE for the upcoming 4.3.
Users of the Karmic development release can upgrade to the latest packages.
Users of our stable 9.04 release can install it from the Kubuntu Backports PPA.
deb http://ppa.launchpad.net/kubuntu-ppa/backports/ubuntu jaunty main
KDE 4.3 Beta 1 is now available in the Kubuntu Karmic repositories.
Packages for Jaunty are available in the Kubuntu Experimental repository. To install these, add this line to your software sources.
deb http://ppa.launchpad.net/kubuntu-ppa/experimental/ubuntu jaunty main
Then refresh and do a full upgrade.