The first Alpha version of KDE 4.0 have been release this May 11th, KDE is a popular Graphics Desktop Environment.
The first thing we will notice is the new user interface which is now using Oxygen theme, which includes a new set of icons. The educative applications included, are also improved i.e. Kalzium, which is a program with the periodic table of the elements, now it will include a 3D molecules visualizer. The included games are also better, with better support for graphics now based on vectors, network games, and artificial intelligence.
The 3D effects are included but disabled, so you will need to enable them.
KDE 4 has a better support for multimedia and hardware, now with Solid and Phonon. Solid is a piece of software that will let us interact with the hardware in an easier way, making some processes automatic. Phonon is the free API to interact with sound and video, and it is free to use to develop new applications for KDE 4.
There is also a new file manager now is Dolphin.
The final release is scheduled for late October 2007, you can download a Live CD based on OpenSUSE, from here
This is an ISO image, you will need burn the ISO in a CD to test it.