You can use dateutils
to make the converstion, you will need two steps:
>>> import calendar
>>> from dateutil.parser import parse
>>> d = parse('10/Jun/2005:05:59:05 -0500', fuzzy=True)
This will create a datetime object
>>> d
datetime.datetime(2005, 6, 10, 5, 59, 5, tzinfo=tzoffset(None, -18000))
And to convert it to UNIX timestamp:
>>> ts = calendar.timegm(d.utctimetuple())
>>> print ts
1118401145