From the original announcement:
PySide is a project providing an LGPL’d set of Python bindings for the Qt framework.
PySide already provides a full set of Qt bindings as well as automated binding generation tools. Since the whole toolset has been made available, the team expects PySide to be valuable not only to Qt software developers, but to people willing to create Python bindings to any Qt-based library, or to any C++ library in general. Although based on a different technical approach, PySide will initially be API-compatible with existing Python bindings for Qt.
PySide is still a work in progress, and some work is still required to stabilize the codebase. This being said, the team believes it is already in a usable state, especially if an occasional rough edge and unpainted surface can be tolerated. Due to practical reasons, the initial development efforts have been focused on Linux, but the team hopes people to join in porting the code to other platforms and to further develop the bindings and tools.
So if you are interested in creating Python bindings for Qt based C++ code or (soon) other generic C++ code, feel free to try out PySide tools and contribute to its development :D.