urllib2 (I'm using 1.13.22 with Python 2.0, but I assume the 2.2 branch does the same) uses the 
POST method on redirect, contrary to RFC1945 section 9.3:

> 9.3  Redirection 3xx
> 
>    This class of status code indicates that further action needs to be
>    taken by the user agent in order to fulfill the request. The action
>    required may be carried out by the user agent without interaction
>    with the user if and only if the method used in the subsequent
>    request is GET or HEAD. A user agent should never automatically
>    redirect a request more than 5 times, since such redirections usually
>    indicate an infinite loop.

Can be fixed in HTTPRedirectHandler.http_error_302 by replacing
        new = Request(newurl, req.get_data())

with
        new = Request(newurl)

so that GET is done on redirect instead of POST.

I suppose the limit of 10 in the same function should be changed to 5, also.