PDK_3.0.i has now been released and contains pre-build QT4.6.2. QT is a graphical runtime that will become the main UI environment in Symbian^4. It makes writing applications for Symbian much simpler and also cross platform, as QT runs in many other OS environments.
This new Symbian^3 PDK contains a pre-integrated version of the Qt runtime environment. It also includes some Demo Application that show case easy is to build great user experience with a few lines of Qt code.
Here is a video demo of some of the things you can do with PDK_3.0.i and Qt: