Here are the steps I've performed to get ViewVC 1.0.5 (http://viewvc.tigris.org/) 
working with mod_python

To avoid Import cycle cd to /usr/local/viewvc/bin/mod_python/
(or whatever the path you have ViewVC installed to) and rename the file
# mv viewvc.py viewvc2.py

Then add these lines to your httpd.conf file:

Alias /viewvc /usr/local/viewvc/bin/mod_python/viewvc2.py
<Location /viewvc>
	SetHandler mod_python
	PythonPath "['usr/local/viewvc/bin/mod_python'] + sys.path"
	PythonHandler handler
	PythonDebug On
	Order allow,deny
	Allow from all 
</Location>

Now you can follow http://localhost/viewvc/ and view contents of your repository

I used this bundle: 
	FreeBSD 7.0-RELEASE
	"Apache/2.2.8 (FreeBSD) DAV/2 SVN/1.4.6 mod_python/3.3.1 Python/2.5.2 mod_perl/2.0.3 Perl/v5.8.8"


To get more info refer to
	http://viewvc.tigris.org/servlets/ReadMsg?list=users&msgNo=4856
	http://viewvc.tigris.org/servlets/ReadMsg?listName=users&msgNo=4857
	http://tomcopeland.blogs.com/juniordeveloper/2006/11/viewvc_with_mod.html

Happy development !

yasir27 at mail dot ru