It also might be worth pointing out the community size based on the frameworks. By looking at their respective IRC channels and/or Google Group sizes you can get a rough estimate how big each of their communities are. Overall, I've found any / all python web framework communities to be extremely helpful and friendly. I say that not to take away from the non-python frameworks because I don't have experience with them.

I couldn't easily find your email so here is a list instead. These books are out right now:

The Definitive Guide to Django: Web Development Done Right: http://www.amazon.com/Definitive-Guide-Django-Development-Ri...

Sams Teach Yourself Django in 24 Hours: http://www.amazon.com/Sams-Teach-Yourself-Django-Hours/dp/06...

Professional Python Frameworks: Web 2.0 Programming with Django and Turbogears: http://www.amazon.com/Professional-Python-Frameworks-Program...

Here are two coming out later in the year:

Practical Django Projects (June or July 2008): http://www.amazon.com/Practical-Django-Projects-Pratical/dp/...

Python Web Development with Django (Sep 2008): http://www.amazon.com/Python-Development-Django-Developers-L...