I am new to python and I would like to do some work on Pitivi.

I have been doing c# for years so I will be able to work out the nuances of the language and work out how it Pitivi fits together but I am having trouble getting the environment set-up!

Could someone give me some pointers on getting started?
I have cloned the git repository. What is the next step from here?
What is a good IDE to use for python or should I even use one?
How do I run the tests? I have tried executing runtests.py but got this error:

Traceback (most recent call last):
  File "runtests.py", line 23, in <module>
  File "/usr/lib/python2.5/unittest.py", line 533, in loadTestsFromName
    module = __import__('.'.join(parts_copy))
  File "/home/derek/Documents/Pitivi/pitivi/tests/test_discoverer.py", line 28, in <module>
    from pitivi.discoverer import Discoverer
ImportError: No module named pitivi.discoverer

Would really appreciate some help!

Derek Ekins