I'd like to know as well. From some other threads, sorry don't have the links, it seems to say you have to include firefox binary in the system/python path.
Looking at the docs for Python bindings, it seems to indicate you could supply path to binary when you instantiate the driver but it doesn't seem to work for me or it's not fully implemented yet or my syntax is incorrect. Here's the error output from python shell:
>>> from selenium import webdriver
>>> d = webdriver.Firefox(firefox_binary='/Applications/Firefox12/Firefox.app/Contents/MacOS/firefox-bin')
Traceback (most recent call last):
File "", line 1, in
File "/Library/Python/2.6/site-packages/selenium/webdriver/firefox/webdriver.py", line 51, in __init__
self.binary, timeout),
File "/Library/Python/2.6/site-packages/selenium/webdriver/firefox/extension_connection.py", line 47, in __init__
self.binary.launch_browser(self.profile)
AttributeError: 'str' object has no attribute 'launch_browser'