The KDE Community has made the release plan for the new Qt4 based version of KDE available. First beta is scheduled for the end of June, first release candidate on end of September and 4.0 stable a month later.
KDE is one of the most popular window manager for the Unix platform and the largest Open Source Qt based project. Availability of an Open Source Qt4 version for Windows platform is said to bring the KDE quality applications to Windows desktops.