PySide exports their version numbers among the version of Qt used to compile PySide in a pythonnic way, you can check it using the variables:
import PySide
# Prints PySide version
# e.g. 1.0.2
print PySide.__version__
# Gets a tuple with each version component
# e.g. (1, 0, 2, 'final', 1)
print PySide.__version_info__
# Prints the Qt version used to compile PySide
# e.g. "4.7.2"
print PySide.QtCore.__version__
# Gets a tuple with each version components of Qt used to compile PySide
# e.g. (4, 7, 2)
print PySide.QtCore.__version_info__
Note that the Qt version used to compile PySide may differ from the version used to run PySide, to get the current running Qt version you can do:
print PySide.QtCore.qVersion()