Django, Retrieve IP location

GeoDjango looks like it will suit your needs. I'm not sure exactly how you would want to direct users, but using the GeoIP API, you can do something like:

from django.contrib.gis.utils import GeoIP
g = GeoIP()
ip = request.META.get('REMOTE_ADDR', None)
if ip:
    city = g.city(ip)['city']
else:
    city = 'Rome' # default city

# proceed with city

The Docs explain things in great detail; I would take a moment to read through them thoroughly.

GeoIP is already mentioned, but I find pygeoip less troublesome to install and no-brainer if you want to embed it in you application instead of installing in Python's site-packages. Still, it works great with free MaxMind databases, e.g GeoLite City one.

Example of use (almost the same as for GeoIP):

>>> import pygeoip
>>> gi = pygeoip.GeoIP(GEOIP_DATABASE, pygeoip.GEOIP_STANDARD)
>>> gi.record_by_addr(ip)
{'country': '...', 'country_code': '...', ...}

This is one solution, from DjangoSnippets; btw, not sure why the code below doesn't use urlparse; but that could be fixed :-)

(Looking at the other answers, it seems you have plenty of options to choose from. This option may not be preferred because it relies on a free 3rd party service.)

from urllib2 import urlopen, Request
import re, socket
from django.conf import settings

domain_re = re.compile('^(http|https):\/\/?([^\/]+)')
domain = domain_re.match(settings.SITE_URL).group(2)

def getUserCountry(ip):
    url = "http://api.wipmania.com/" + ip + "?" + domain
    socket.setdefaulttimeout(5)
    headers = {'Typ':'django','Ver':'1.1.1','Connection':'Close'}
    try:
        req = Request(url, None, headers)
        urlfile = urlopen(req)
        land = urlfile.read()
        urlfile.close()
        return land[:2]
    except Exception:
        return "XX"

Note from WIPmania: "Using API is free for any purpose, personal or business, if you are making fewer than 10.000 requests per calendar day. A simple yet powerful API allowing you to query the WorldIP database with a single link."

You could create a view which gets the user's IP and then issues an HTTP redirect which will cause their browser to load the page you want:

def redirect_based_on_ip(request):
    ip = request.meta['REMOTE_ADDR']
    if ip == SOMETHING:
        return HttpResponseRedirect('/something')
    elif ip == SOMETHING_ELSE:
        return HttpResponseRedirect('/something_else')
    # ...

You might find the SubnetTree library for Python helpful if you want to test to see if an IP is in a particular block.