O que devo fazer para que o PyQt4 funcione no Ubuntu?

Question

Instalados os pacotes python-qt4 e pyqt4-dev-tools no ubuntu

Python 2.6.6 (r266:84292, Sep 15 2010, 15:52:39) 
[GCC 4.4.5] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from PyQt4 import QtGui
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: the sip module implements API v8.0 but the PyQt4.QtGui module requires API v7.1

O que devo fazer para que o PyQt4 funcione?