Using GIO in Python 3
gio is a PyGTK module, and is not available for Python 3 because PyGTK itself is deprecated. If you want to create a GTK+ application in Python 3, you will need to use its replacement: PyGObject. In the case of Gio, you import it like this.
$ python3
Python 3.2.2 (default, Sep 5 2011, 21:17:14)
[GCC 4.6.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from gi.repository import Gio
Such documentation as exists can be found here. Best of luck!