I've just released the first version of Python Call Graph. I haven't
tested it too much so don't expect it not to crash :)
An example of its output is:
It's easy to use... you just need Graphviz installed and in your path
and a few lines of code changes.
More details at http://pycallgraph.slowchop.com/
If you have any problems, don't hesitate to ask here or email me directly.