Source:

Untar:

tar -xvzf sane-pygtk-XXX.tar.gz

Install (as root):

python setup.py install

Or run from the source directory (does not need to be root):

python sane_pygtk.py

configuration file:
Use the configuration file to set default values

To create the default configuration file just run sane_pygtk.py

Example:

~/.sane-pygtk.cfg

[settings]
scanner = 1