Packages for the release of the QtCreator 2.1 Beta 1 are now available for Kubuntu 10.10.
Bugs in packaging should be reported to kubuntu-ppa on Launchpad. Bugs in the software to QtCreator.
Users of 10.10 Release Candidate can install it from the Kubuntu Beta Backports PPA.
If you want to try out Qt 4.7 and the interesting new world of Qt Quick ("from now on the way to make GUIs"), Kubuntu 10.04 users can try it from the experimental PPA. The Qt Creator packages there have Qt Quick designer integration.