Saving tif file from tricky webserver

[schweet1]

Greetings,

I am attempting to automate accessing and saving a file (a TIF) from
the following URL:

http://patimg1.uspto.gov/.DImg?Docid=US007376435&PageNum=1&IDKey=E21184B8FAD5

I have tried some methods using urllib, httplib, and
web32com.client(InternetExplorer), but haven't been successful.
Currently I am using (in Python 2.5)

import webbrowser

url = [see above]

webbrowser.open(url, new=0, autoraise=0)

When this is run a windows popup dialog opens asking me to Open, Save,
or Cancel.  However, if I query multiple such URLs, I do not want to
have to respond manually.  Is there a way I can use Python to save the
TIF?