When the KDE project announced KDE 4.0, it was pretty clear that this was just first and far from complete version of KDE4. Instead, lots of features would be added with each new version. KDE has now announced the first Alpha of KDE 4.1, the final version is slated for late July. KDE 4.1 is based on Qt 4.4, which means improved performance, WebKit browser engine, and widgets-on-canvas. It has also added Dragon Player (KDE3 Codeine spin-off), Akonadi (new storage framework for PIM applications) and KDE-PIM (although not Akonadi-based yet) and large rewrite of the Plasma desktop shell.
This is just the first preview so don’t go installing this on your workstation or regular desktop PC. If you want to try out the new features or help in the bug hunt go on ahead, but you’re doing it on your own risk.