The first development snapshot of KDE 4, codenamed Krash, has been released and packages are available for Kubuntu Edgy. These are intended for developers only.

They install to /usr/lib/kde4 and can be installed alongside your existing KDE 3.

Kubuntu Edgy
  • deb http://kubuntu.org/packages/kde4-3.80.1/ ./

These packages are available for i386.

Instructions:
  • Add the apt sources line above.
  • Install kde4base-dev, this will uninstall the normal qt4 packages and install the qt4 kdecopy packages.
  • These KDE 4 packages install to /usr/lib/kde4 so run:
    • export LD_LIBRARY_PATH=/usr/lib/kde4/lib
    • export KDEDIR=/usr/lib/kde4
    • export PATH=/usr/lib/kde4/bin/:$PATH
  • Run some programmes. Konsole seems to work. Good luck.

http://kubuntu.org/announcements/kde4-3.80.1.php